There are situations where it does actually cause problems when you want to merge the branch again. It knows that those specific commits have already been reverted once, so it doesn't apply them...

See also: https://github.com/git/git/blob/master/Documentation/howto/revert-a-faulty-merge.txt (especially line 56)

Basically you need to revert the revert, before re-merging the fixed branch. Otherwise you will lose commits without noticing!