Was unable to use potions and repair materials in Cyrodiil. Relogging fixes the issue for some time, but it keeps reocccuring. Seems like it happens after using the same item multiple times. Had no issues using food or placing siege, probably because i don't use those things that often, but other players were complaining about issues with siege as well. Didn't test outside of PvP, so i don't know if this is related to Cyrodiil or if it happens in PvE too.