Steps to reproduce

1. Load the test world, MCPE-119647.mcworld
2. Flip the lever to turn off the repeating command block in the center.
3. To repeat the test, flip the lever again to turn the repeating command block on, then press the button on the impulse command block.

Expected result

All of the minecarts stop on the inactive powered rails, and all of the villagers live.

Actual result

Half of the minecarts do not stop, so half of the villagers die.

When powered rails face east - west, they should behave exactally the same if a minecart bounces one way or another. Sadly, this is not the case. When a minecart with a mob/player (didn't attempt with other type, but suspect problem applies to those as well) travels directly north into an unpowered east/west rail with a block on the west side, and a set of rails on the east side, the minecart is supposed to stop, until the rail is powered; at which point, the minecart is supposed to move onward on the new rail.

What happens though is that in the described configuration, the minecart acts as if the powered rail does not exist, and that it is instaid replaced with a turning rail. Creating an instant turn that breaks minecart stations and mob transporters. Curiously, if you reverse the directions and approach from the north side facing south, and have the block on the east side, the problem is resolved, and is completely fine. 

That's great, but it means that I have to either redesign, modify, rebuild, or wait for a bug fix to use my ghast blaster.

The image below is not the actual scenario, but a complete replica. North is red.