I notice this also when I do a "Download Report" from LOTW. I use the Manual update option which means that I get to see any differences from previous imports. There are lots!
While it is a bit boring to do manual checking, I have come to the conclusion that people move around a lot! I still do the manual route, but I no longer get bent out of shape when I see a discrepancy such as 4 vs 6 character grid references, changing Counties and zones, etc. I only look for obvious errors. My original goal of a "Golden" logbook has gone out the window long ago.
Maybe Clublog has something that could help with this problem, but so far I still stick to manual updates and checking. Even LOTW has a disclaimer that essentially refers to GIGO (Garbage in Garbage out). I don't think you'll ever get it perfect. It is up to you to decide what is good enough.
As far as awards are concerned, when or rather if I went to apply for an award, I would then do a thorough check on the subset of qsos that I would be submitting.