It is an old bug as i remember, fixed once, but returned (mojang likes retro? )

When you exit a minecart and you are riding beside a wall, it can happen, that you stand on other side of wall instead of inside a tunnel (nether for example. Luckily i cannot tell if you would even drop outside when exiting at a tunnelbridge above lava in nether).

(This is not veryfied with 1.9.4 but with 1.9.0) When standing on one side of an Iron Bars and exit a horse, it happens that you stand on the other side of the Iron Bars.
Was a great timesaving advantage on nitrado event map last time.

I might add, i died because of that issue by exiting minecart (in nether, but i don't think that matters), died because of "buried alive"!