Screen brightness is being reset to maximum after reboot

UPDATE: I tried this and it worked for me (so far).

1. turned off second monitor
2. unplugged the thunderbolt/display connection from back of iMac
3. manually put iMac to sleep (not letting energy saver do it)
4. main monitor woke up this am and… iMac screen did NOT reset to max brightness. Seemed to stay put.

While that is a PITA, it sure beats a 30-min calibration cycle daily.

Definitely some Catalina issue with 2nd monitor.

My machine is a Retina 5K late 2014 maxed out.

Thanks to others on here who have been posting clues. Helped me figure it was a 2nd monitor issue (well, a Catalina issue RE 2nd monitors). Hope Apple fixes this "feature." And no, this never happened before Catalina for me.