Since a couple of versions ago, and still in this snapshot, exiting a minecart it will not check every surrounding block (in a circle) for ways to exit.
It seems that it will in any case not let you exit one chosen direction.
(As tested, north and south).

See the screenshot for more details.

The player cannot exit in the red area, even though there is NO block/obstruction.
The player will spawn in the middle (above the minecart).

Please fix this!