He can't completely compose himself for the whole interview. There were times where he had a very pensive look, but then he would spaz out with a maniacal laugh without warning.

I'll give him a little slack here. It was obvious to me that the recording was edited so that the English dub aligned closely with what Putin was actually saying. In real-time interpretation, there's a greater delay in getting the English interpretation, so when Putin said something that Tucker found funny, it was probably several seconds before that was interpreted into English.