Ultimate Bet Rebuy

[Destin Stone]

Hi. Im really not sure about this one and I couldnt find my answer anywhere.. Im also not very familiar with Rebuys. I was in a UB rebuy last night close to the first break when a player who is all in wins a 2380 dollar pot. Immediately after the chips were pushed to him his stack jumped to 5380 and in the chat box it said they had rebought twice. Is this legal?? are you allowed to rebuy when all in before the hand is over?? Is this allowed in all rebuys or only on UB?? Any help in this manner would be greatly appreciated!