[aw3c2]

I often have Unison not notice file changes until I repeatedly scan or sometimes even until weeks later. If I new a better alternative I would not use it.

[Tho85]

They use some kind of heuristic to make change detection faster, see their documentation: http://www.cis.upenn.edu/~bcpierce/unison/download/releases/...

Maybe that's the root cause of your issues?