Vlan randomly dropping

We are experiencing an issue where a vlan is randomly going up and down on one of our switches and then stabilizing. Neither the uplink interface nor the host interface are bouncing. What could be causing this to happen?

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Log Buffer (4096 bytes): eb 14 04:12:07 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:12:17 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:12:17 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:12:48 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:12:48 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:12:53 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:12:53 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:12:59 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:12:59 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:01 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:01 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:05 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:05 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:06 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:06 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:14 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:14 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:18 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:18 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:20 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:20 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:24 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:24 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:26 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:26 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:32 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:32 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:42 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:42 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:46 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:46 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:13:46 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:13:46 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:14:18 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:14:18 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:15:26 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:15:26 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:15:57 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:15:57 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up .Feb 14 04:16:09 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to down .Feb 14 04:16:09 CST: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan666, changed state to up Uplink FastEthernet1/8 is up, line protocol is up (connected) Hardware is Fast Ethernet, address is 7001.b5f3.8f8a (bia 7001.b5f3.8f8a) Description: Uplink MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec, reliability 255/255, txload 52/255, rxload 53/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s, media type is 10/100BaseTX input flow-control is off, output flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:00, output 00:00:04, output hang never Last clearing of "show interface" counters 23:57:55 Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 32 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 20994000 bits/sec, 2344 packets/sec 5 minute output rate 20532000 bits/sec, 2108 packets/sec 104294441 packets input, 114856748374 bytes, 0 no buffer Received 485390 broadcasts (458835 multicasts) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 458835 multicast, 0 pause input 0 input packets with dribble condition detected 95047409 packets output, 110239191014 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 unknown protocol drops 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 pause output 0 output buffer failures, 0 output buffers swapped out Host FastEthernet1/3 is up, line protocol is up (connected) Hardware is Fast Ethernet, address is 7001.b5f3.8f85 (bia 7001.b5f3.8f85) Description: Server MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s, media type is 10/100BaseTX input flow-control is off, output flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:04:05, output 00:00:00, output hang never Last clearing of "show interface" counters 23:58:45 Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 14000 bits/sec, 5 packets/sec 5 minute output rate 46000 bits/sec, 9 packets/sec 661276 packets input, 261701907 bytes, 0 no buffer Received 5957 broadcasts (3610 multicasts) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 3610 multicast, 0 pause input 0 input packets with dribble condition detected 1076200 packets output, 676022355 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 unknown protocol drops 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 pause output 0 output buffer failures, 0 output buffers swapped out Vlan Interface Vlan666 is up, line protocol is up Hardware is EtherSVI, address is 7001.b5f3.8fc1 (bia 7001.b5f3.8fc1) Description: Private Network Internet address is 192.168.1.20/24 MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive not supported ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:00, output 00:00:00, output hang never Last clearing of "show interface" counters 1d00h Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 1000 bits/sec, 2 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 219640 packets input, 25640446 bytes, 0 no buffer Received 0 broadcasts (0 IP multicasts) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 14057 packets output, 2612243 bytes, 0 underruns 0 output errors, 0 interface resets 0 unknown protocol drops 0 output buffer failures, 0 output buffers swapped out