Thanks for the recommendation idlemind, I will dive into that.
I actually got my issue solved this afternoon. The answer was to add a filter rule to forward "new" connections from the vlan (source) address.
I thought about that and went down that path. I tried this with high hopes: https://stevedischer.com/pmtu-and-mss-d ... -mikrotik/Sounds like you have a MTU problem on your network