Seems I spoke too soon. Just happened in 15w44b too 😞
Also confirmed for 15w44b.
Seems to be fixed for 15w44b!
@Daniel Brunett: I also lose items on shift-click retrieval.
I'm also experiencing this issue.
My rails are mostly located in the Nether. As I reach the loaded boundary the game freeze. All I can do is restart the client. Most of the time this works without problems, but some times I've been thrown from the minecart and into the lava lake below (losing all of my stuff).
The bug is indeed caused by sitting in a minecart thats resting on a ladder for too long! Didn't take long either, the client crashed after only 2-3 seconds.
Still happens in 15w43c. It seems I may have forgotten to include a line from the previous console log - or perhaps this is new in this snapshot (notice the line @ 20:31:29 below).
Console output on crash:
[20:31:29] [Client thread/WARN]: Null returned as 'hitResult', this shouldn't happen!
[20:31:41] [Server thread/WARN]: <playername> was kicked for floating too long!
[20:31:41] [Server thread/INFO]: <playername> lost connection: TextComponent{text='Disconnected', siblings=[], style=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=null, hoverEvent=null, insertion=null}}
[20:31:41] [Server thread/INFO]: <playername> left the game
[20:31:41] [Server thread/INFO]: Stopping singleplayer server as player logged out
My minecart elevator is 16 "floors" tall, and this just happened as I reached the top floor (before I was able to exit the last minecart). I'm going to test whether the bug is simply caused by sitting in a minecart thats resting on a ladder for too long. Perhaps it's not related to the quick dismount/mount activity while using minecart elevators.
Still happening in 14w21b. Just lost my precious horse 😞
Confirmed for 15w45a. The client no longer crashes, but exits gracefully with message "Flying is not enabled on this server" (see attached screenshot).