Issues with VLANs and Multiple Gateways

eptesicus

Greetings, all. A little setup for my question...
I'm running TorGuard VPN in HA, so I have that and WAN setup as gateways:
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I'm routing 2x VLANs to go over the TorGuard VPN gateway, and the rest or routing over the WAN. I have outbound NAT'ing setup for the VLANs to exit out the right gateway:
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The issue I'm having is that a particular VLAN, v110_Wiferino (10.0.110.0/24), tries to route over the VPN (although not configured to do so, but fails, even though it's set to route over the WAN. The only way around this is to set my last rule in the VLAN to pass the traffic through the WAN. No other VLANs need to be setup this way.

This VLAN only works if the last rule has the WAN set for the gateway:
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Another VLAN that works fine over the WAN, without the need to specify it in the last rule:
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An example of a VLAN configured to route over the VPN:
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What's wrong with my configuration? Why does it work on other VLANs, but not v100_Wiferino without changing the rules? The weird thing is that it worked fine for a couple weeks before last night, when it attempted to go over the VPN instead, but had no connectivity.