Verification builds:
1.2.0.15 Retail

Summary:
When dismounting a vehicle or mount* in a 2-high space, the player can get elevated through the ceiling above their head. This can be really awkward for survival maps where you can end up in danger unexpectedly. It can also be used to get onto the nether roof in survival.

Steps to Reproduce:

1. Ride a vehicle or mount* into a two high gap
2. Exit or dismount the vehicle or mount

Observed Results:
The player ends up on the platform above their head.

Expected Results:
The player should dismount to a suitable gap beside the vehicle or mount.

Screenshots/Videos attached: Yes

Notes:
*List of vehicles and mounts tested:

• Minecart
• Boat
• Pig with Saddle
• Horse