I am using Keynote 12.2.1 and don't have this problem
Try resetting Keynote, its known to sort these type of issues
Complete all of the following steps, in the order listed:
- uninstall Keynote; for this procedure to work, an application removal tool must be used, App Delete has a free trial and works for this procedure. It can be downloaded from the developer’s website here: http://www.reggieashworth.com/buy.html
- empty the Trash (Finder > Empty Trash)
- restart the Mac (Apple Menu > Restart) and immediately press the shift key on the keyboard, release the shift key when the Apple icon appears. Start up will take longer than usual as the Mac is performing a software repair of the start up drive
- after the Mac is fully powered up, restart the Mac normally: Apple Menu > Restart
- reinstall Keynote from the Mac App Store Application and test