Eigrp flap issues, holding time expired.

My setup look like this. Core 1 <-> layer 2 port channel 1 & layer 3 port channel 2 <- > core 2 .

And new cisco-edge switch was added to the core with default gateway pointing to new hsrp vlan 340 on core pair. There where few native vlan mismatches as I was still making changes. Long story short, while making changes for native vlan mismatch, layer 3 loops and layer 2 loops flapped eigrp ne consistently. I am trying to find traces of loops but cannot find anything in the logs. I never seen this happen before while configuring new hsrp and layer 3 vlan. There where no spanning tree loops as per sh span tree summary. Also I observed that one of the down link, primary switchport on edge switch went in to err_Disable state. I am trying to figure out, if this is case of layer 3 loops. **What are some design precautions and config design elements that I need to verify to make sure this dont happen again**

Jul 19 12:10:57 utc: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet4/0/11 (999), with cisco-edge switch GigabitEthernet0/25 (240). (CISCO-CORE_switch)

Jul 19 12:12:16 utc: %SYS-5-CONFIG_I: Configured from console by areh on vty0 10.32.0.10

Jul 19 12:12:26 utc: %SW_MATM-4-MACFLAP_NOTIF: Host 0024.8088.8088 in vlan 340 is flapping between port Gi4/0/11 and port Po1

Jul 19 12:12:28 utc: %SW_MATM-4-MACFLAP_NOTIF: Host 0024.8088.8088 in vlan 340 is flapping between port Po1 and port Gi2/0/11

Jul 19 12:12:33 utc: %HSRP-5-STATECHANGE: Vlan922 Grp 0 state Standby -> Active

Jul 19 12:12:33 utc: %HSRP-5-STATECHANGE: Vlan326 Grp 0 state Standby -> Active

Jul 19 12:12:33 utc: %HSRP-5-STATECHANGE: Vlan901 Grp 0 state Standby -> Active

Jul 19 12:12:33 utc: %HSRP-5-STATECHANGE: Vlan222 Grp 0 state Standby -> Active

Jul 19 12:12:33 utc: %HSRP-5-STATECHANGE: Vlan600 Grp 0 state Standby -> Active

Jul 19 12:12:34 utc: %DUAL-5-NBRCHANGE: EIGRP-IPv4:(100) 100: Neighbor 10.22.3.20 (Port-channel2) is down: holding time expired

Jul 19 12:12:36 utc: %HSRP-5-STATECHANGE: Vlan800 Grp 52 state Standby -> Active

Jul 19 12:12:36 utc: %HSRP-5-STATECHANGE: Vlan330 Grp 0 state Standby -> Active

Jul 19 12:12:41 utc: %HSRP-5-STATECHANGE: Vlan922 Grp 0 state Active -> Speak

Jul 19 12:12:41 utc: %HSRP-5-STATECHANGE: Vlan800 Grp 52 state Active -> Speak

Jul 19 12:12:41 utc: %HSRP-5-STATECHANGE: Vlan326 Grp 0 state Active -> Speak

Jul 19 12:12:41 utc: %HSRP-5-STATECHANGE: Vlan330 Grp 0 state Active -> Speak

Jul 19 12:12:41 utc: %HSRP-5-STATECHANGE: Vlan922 Grp 0 state Active -> Speak