This doesn't have the same issue as mass updates, but
it doesn't hurt to change this away from tag_string_diff as well
Aliases/Implications still do this but considering this has been the case
for 4 years now I don't believe this to be a problem
Resolving aliases here is not great. Just mass update nothing in these cases, that's much safer.
Using tag_string_diff also wasn't a very bright idea, this too can result in both tags being removed
