Never could get Logic to configure correctly. Was able to set up Live and it did not send T2-T4 back to T1.
Don’t know what the issue was.
But, given that there were other things about the setup, one being that I couldn’t use the EQ features in Heat (it is my audio interface), I decided to not use Overbridge at all.
I’ve never experienced this problem.
What you think is T1 might be the mains out?
How did you route the busses? Which version of outs did you use for OB?
A detail explanation of your routing is necessary.
I could try the same routing and see if it happens (mk1 here but I think there’s no diff with OB)
I’ve just tried and it works as expected with my A4 mk1.
Did you check that in your OB control panel all the inputs are selected?
Here is the project I’ve used.