How do I stop portrait screen reverting to horizontal orientation after 10.15.4 update?

I have two 22" external screens connected to my MBP 15" 2016 with Radeon Pro 460 4GB and Intel Hd Graphics 530 1636 MB. One of the screen is oriented with the normal horizontal display, the other in portrait orientation.

After the 10.15.4 upgarde, the portrait oriented screen had reverted to horizontal display. After an upgrade, I could accept this so I tilted my head 90° while I selected System Preferences > Displays > Rotation and changed it fro the default Standard to 90°

When I powered off the screens last night, and put my MPB into sleep mode, the screens were as I had configured them. When I woke the MBP this morning, the portrait screen had reverted to Standard Rotation and I had to go through the whole "tilt head 90° and change settings" process again.

My question is, How do I stop portrait screen reverting to horizontal orientation after 10.15.4 update?

Should I revert to the previous version where I did not have this problem, or is there an easier fix?

RedNectar