Strang Configuration?

I have an interesting situation at work, where something is most definitively NOT configured by any sort of standard, and I honestly have no idea how this even works, so I figured I would throw this out there and see if anybody can shed some light as to how the heck this is even working.

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I have a 600Mbps link between my main site and my DR. First I will list the main site relevant config.

MAIN SITE:

interface TenGigabitEthernet1/1/6

switchport trunk allowed vlan 1,313

switchport trunk native vlan 350

switchport mode trunk

interface Vlan1

description MAIN_NET

ip address 172.17.0.5 255.255.0.0

ip pim sparse-dense-mode

end

interface Vlan313

ip address 10.254.255.2 255.255.255.252

end

Pretty striaght forward stuff. Seems like a trunk port that I think is running over a L2 (Probably MPLS link) to our DR site

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THEN, I get to the DR Switch

interface GigabitEthernet0/19

switchport mode trunk

end

interface Vlan1

no ip address

no ip route-cache

!

interface Vlan333

description Integral

ip address 172.17.1.150 255.255.0.0

no ip route-cache

!

ip default-gateway 172.17.0.5

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This would all make sense. . if the 172.17.1.150/16 were on vlan1. . because that would match with what is at my main site, but its not. It has been changed to vlan 333 here, and I honestly just dont know how that is possible.