I’ve had similar issues on a similar setup. Quattro and Multi Compact both no longer ignoring AC - #7 by Starcruiser
Happened on both a Quattro setup and a multi compact.
Solution so far is to remove all assistants and start afresh. I’ve also elected to utilise the Cerbo to switch the Quattro via relay2 using Node Red and a wired link to the temp input on the Quattro.
Early days but so far so good.