Photos randomly merging unprompted (appears like a poor double exposure)

When going through photos in the details view, when clicking or pressing the arrow to scroll through photos, it will randomly merge a photo with the previous photo without any prompting (beyond clicking through to the next photo).

This started approx a month ago and has been getting progressively worse. The issue is amplified by going through photos quickly so you cannot look through a large gallery of photos at a fast pace or it will start merging far more random photos.

It ends up looking like a terrible double exposure where one of the merged photos goes black and white and the other ends up extremely oversaturated.

It does not rectify itself upon export rather it exports as the incorrect, merged version.

The only way to get the original photo back is via the versions tab and selecting a previous version however it does not recognise the merge as an action as you cannot control or command z to undo it.

I do have photos and screenshots demonstrating the issue however will not attach in this forum for privacy reasons.
I confirm that I am working on the latest version of Lightroom (there are no outstanding updates available) and am working from a MacBook Pro.

Any assistance with rectifying this would be greatly appreciated!

Thanks! :)