So in AH and MH 9 with the new update sometimes when people get in the two back seats, they standup through the helicopter. Mostly the people on the pilots side.

Some people start floating around the chopper if they get onto the side step.

Sometimes getting into the pilot seat result in you getting stuck under the chopper in a sitting position and unable to move, get in or out. The only way is to respawn.

In other cases, you end up under the chopper but have the option to get out but when repeating the procedure same thing happens. After a while randomly you get into the chopper.

What I noticed however, is quite often when you enter the chopper as a pilot, it looks like you are getting under the chopper for half a second before you get in. Seems like sometimes it just gets at stuck at that point.