My understanding is the maximum height at the start of a match is 15’‘. However during the match the robot can be taller than 15’‘. My question is if during a match (specifically in autonomous programming) you need to reset the robot in the starting position, does the robot need to be under 15’’ during the in match reset?
No, this is not required. The reset only needs to be within the bounds of the Starting Position, which has no height limit. (the 15" limit at the start of a Match is a Robot restriction, not a Starting Position restriction)