Likely resulted from the fix to MC-129863/MC-131116/MC-130572/MC-132482.
This can happen in many different cases:
Placing a lily pad within yourself (MC-667)
Closing a door on yourself
Closing a fence gate on yourself
Having a piston push a block into your feet
Solid plants growing within a player (e.g. bamboo, trees)
Intersecting a falling block after it lands
Having a piston push a block into your head (likely intended - especially if the pushed block comes from above, and makes for easy entrances to one-block-high passageways)
Using an ender pearl to enter a one block high area (likely intended - stops you from suffocating, and sounds very useful)
Closing a trapdoor on yourself (likely intended - makes for easy entrances to one-block-high passageways, assuming the trapdoor is waist height)
It would be best if all intersections with the top half of the player still caused them to start crawling, but all intersections with the bottom half would not.
Linked issues
discovered while testing 2
is duplicated by 52
MC-147277
Certain events cause player to perform swimming animation
Resolved
MC-147292
Player falls into floor and crouches when closing a door on the same block as player
Resolved
MC-147293
When standing on the block directly below a door/trapdoor, player will get in swimming animation if they toggle the door/trapdoor.
Resolved
MC-147297
player becomes 1 block tall inside a closed door
Resolved
MC-147300
.
Resolved
relates to 3
Attachments
Comments 7
Relates to MC-147264
Caused by the exact same bug as MC-147264, this is technically a duplicate just under different circumstances
Trapdoors still cause the behavior, not to mention it isn't crawling, just "swimming" in air, it's way too bizarre to be normal behavior.
The only intentional behavior is when it is to prevent unintended suffocation. That is not an issue with trapdoors at all, so it doesn't fit the intended criteria for "crawling" to occur.
migrated
Also could be considered as found while testing MC-141824 as per the comments on MC-667.