@DanH found it! The AVP Bypass soft bypass container had something weird going on - you can see its bypassed but didn't have a control to toggle it. Turns out I didn't need it so re-organised the contents and it works.
Phew! Only 4 hours lost ๐ข
Thinking about it I reckon I moved that AVP Bypass container out of Branch container which probably caused the issue. The branch would normally control the container bypass... I guess...