LR not updating second screen (not solved)

[Frodo]

I have two screens NEC PA242W on the left and a cheap AOC on the right). The right screen is my working screen with sliders, etc. The calibrated left screen allows me to see the impact of any editing.  My problem is that my left screen often does not update.
The first is an uncropped image - both screens show the original image.  I then cropped the image and the left screen updated this. But when I shifted the crop,  the left screen did not update (second photo). I then selected "autotone" and then the left screen updated (third photo).
Why did the left screen not update when the crop was shifted?
This is a real nuisance and help would be appreciated.A workaround would be a shortcut key that refreshes the screens (like "autotone" does).
Running latest LR Classic on Windows 10, i7 8700 CPU, 16GB RAM, NVidia GTX 1650 GPU, program files and catalog on Samsung 970 (?) SSD.

Thanks

[Frodo]

I have the same issue as this person (note that he spelled "previous" as "previews").
https://feedback.photoshop.com/photoshop_family/topics/refreshing-crop-view-on-secondary-display

[Frodo]

As suggested in the link in the post above, resetting LR preferences (pressing alt - shift when starting LR) solved the problem!

[Frodo]

The problem is back again.
I don't want to have to reset my LR preferences for each session!
Suggestions appreciated.
Even a shortcut key to update the second screen would suffice.
Thanks

[saiguy]

I am on Mac and LR 2019CC. I remember rare occasions when some adjustment I just did didn't update on 2nd monitor. I think it was mostly, perhaps only, with the crop tool. Then I would do a small adjustment, like increase exposure by a bump with the arrow key, the crop would then update, and I would just use the arrow key to bump it back.

I work only with scanned images and my crops are only to remove anything outside the image area. In other words they are very tiny crops.