Lightroom Classic 100% view pixellated in Develop, but not in Compare mode

[joek22042124]

I updated late October 2020 and I'm using a 27" iMac with 32GB RAM. When in Develop mode at 100% my images are pixellated, which robs them of sharpness so I can't work on them. In Compare mode they revert to perfect clarity. Going from Compare to single view the image remains perfect until I move it, at which point it reverts to pixellated (small pixels but image destroying) although I can move both images happily without loss of clarity in Compare mode.

Has anyone any clue as to why this is happening?

[dj_paige]

Show us a screen capture. Click on the Insert Photos icon. Do not provide the screen capture as an attachment.

[joek22042124]

[joek22042124]

Top is Compare and bottom is Develop Mode

[joek22042124]

The first ones I sent do not appear to be as sharp as my screen shots. Maybe they are being enlarged. So I've repeated the exercise and hope this isn't being annoying!

Compare mode