Dark images when viewing in Library & exporting but fine in Develop mode

On certain images throughout a catalogue the images appear very dark when exporting or sometimes viewing in library mode.

They look fine and are correctly exposed in the develop mode but after exporting they are dark. It's only in a few images, maybe 1 image in 100 will appear like this. The only way to correct it is to guess at the correct exposure and increase it 1 or 2 stops and through trial and error I get the correcly exposed exported image.

Needless to say this is extremely frustrating...

Anyone know how to fix this bug or what can I do to sort this?

Running;

LR classic v12.1

MacOS Big Sur 11.7.3