i figured out then when i build a house, let's say 3x3 surrounded by walls, a roof and having one wooden door to enter the house and a bed inside, the villager is not able to enter the house when directly before the door there is a dirt path. he just stucks and/or is running around the house trying to reach the bed.

i tried it in creative mode and also in normal mode but the behavior is everywhere the same. i was even able to see the same behavior in a generated village. see the screenshots below. 

to make it work currently is to place right before the dirt instead of a dirt path a normal dirt block.

Example:

a generated village (seed 4473763675001208156 at position 788 63 1244) where the villager is not able to enter the house at night:

after replacing the dirt path before the door he immediately enters the house and sleeps

i attached also the exported world