You’re not missing anything, that should work fine.
Can you confirm you are only using CQ-MixPad for control?
Could you also send us a copy of the show please? (via support.allen-heath.com).
Once you’ve stored a copy, please carry out a hard reset and check again.
Doh, sorry wrong alarm! I accidentally muted the FX return via mixing station during development yesterday and then forgot about it (since it’s not visible in the mixpad UI)