Track Data correct Album Art wrong

Hi,
I have rearranged my libraries and had all the meta data re-constructed.
All the track data is good - and even the background image is often right - but the majority of album covers replicate just one.
I have tried to get it to match, and it knows exactly which album as I just select the track in the album it proposes. It says it is downloading meta data, and then does not.
As there are probably over 1000 albums that are incorrect, I cannot do this manually. Does anyone have experience of this, or how to solve it?
Best,
Nick

I think I’ve found that by forcing a refresh that it is sorting this out.