I have buttons 1-5 in bar №1 bound to digit keys 1-5, and they worked in pet battles before. Since the update to Dominos v. 5.3, these keys no longer function with Dominos enabled. With Dominos disabled, they work. This has been happening both in WoW 5.2, and WoW 5.3. I'm certain I hadn't changed any keybinds.

Have you downloaded the release version? (It's different than the betas)
What are your override bar settings? Dominos uses the bindings from that bar for the pet battle bar now.

Update: Try 5.3.1 it should fix your issue :)

Thanks for answering. I'll be able to verify in ~12 hours, will report back.

Reporting back, issue fixed. Thank you!