Having problems with erratic behaviour when reordering images

I have been using LR for many years and have had no problem with dragging images in the film strip to reorder them. Recently, this has become very erratic. Sometimes it works okay other times, even though the cursor shows I have picked up the image, when I drop it it either just returns to the original place, drops somewhere random or even sometimes another image will randomly change place.

I have tried shutting down and restarting both my laptop and LR but the problem persists. I have the order set to, ‘custom’. I have also collapsed and reopened the filmstrip. The problem also occurs in the library module using grid view.

What once took my 5 minutes is now taking hours, it’s very frustrating. Any help would be great.

Dave