Are you using my newest driver? [DRIVER] Zooz ZEN Switches Advanced (and Dimmers)
What firmware is your device (at bottom of device page). Are all 3 the same firmware?
I would switch to my driver, get your settings how you want it. Then run Configure.
For any new-ish ZEN77 my brightness correction feature should be hidden because Zooz baked it into the firmware, so that should not be in play.
Level 99 should be automatically converting to 100 on my driver, I do this so on dashboards or external apps it shows as being fully on. So really, it should not be possible to even see level 99 in the attributes, it would always be shown as 100.
Anyway... after running the configure with my driver turn on debug logging. Replicate the issue and post a screenshot of the logs. Also would like to see a screenshot of the current states afterwards.
May not be a bad idea to post a screenshot of your settings also.