Tempo is changing during record

[Flash]

Hey guy's, I have this song that the tempo changes during the chorus. Now lets say we're recording a vocal track and the singer messes a part up. I go in and do a punch in at the place of the mess up. Some how it seems (all) the tempos get set to whatever the tempo is at the place of the punch in and then the song is all out of sync. I have to manually go back in to all the verses and chorus's and reset the tempo. This is time consuming and really pisses some people off, including me. Do I have to split the tracks at every verse and chorus? All or most all of the tracks where done in one take. It seems this only happens during a punch in. Do I have a setting missing or something? Any help out there would be appreciated.