Audio problem: When Phil is playing the piano with the jazz group, we hear three glissandos (dragging of the fingers over the keys starting from high to low), yet we see his hands only do one. We hear the first two happen while we see his hands playing something different.
Audio problem: When Phil is dressed as an outlaw and pretending to be "Bronco" his Clint Eastwood impression voice is out of sync with his lips.
Audio problem: At the party when Phil is playing the piano, there are several shots of the other band members. Multiple times they are seen playing their instruments, but they are never heard. The most obvious example is right before Phil finishes up his set. The saxophone guy is playing but you never hear it.
Audio problem: When Phil is building his final snowman, Rita says, "Why can't I look?" but her mouth does not move. (01:32:50)
Answer: Old fashioned hotels have a single boiler for all the hotel rooms. Once the hot water reservoir is used up there won't be any more to use until the reservoir is refilled. This only happens once every few days.
lionhead