I had 1500 caps exactly, and wanted to upgrade my armory for 1500 caps. It said I didn't have enough caps. Waiting for a dweller to level up so I got 1519 and I was then able to upgrade and ended up with 19 caps left over.
Sometimes after an attack of molerats, radroaches or raiders some dwellers HP bar is still visible despite the attack being over.
Sometimes Mr Handy can pass through a room that has resources to be picked up without picking them up.
I can confirm a bug where unarmed dwellers can start to run around aimlessly from spot to spot in the same room as if trying to get a good aim with their fists rather than doing anything useful. And I'm not talking about pregnant women or children that will run away all together.