When standing on a village road edge (at least 1 block higher than the surrounding blocks) then you slide off it like if there was water flowing over the block. I have only tested this with automatically created village roads in villages. Might happen if you use a spade (right click on dirt block) and make your own road.

EDIT: See screenshot for clarification. Village road on an edge will push you off when trying to stand on it.

To reproduce: stand on flat groud, put a dirt block on top of the ground, right click the placed dirt block with a spade to create "road" texture and then jump up on it. It should slide you off and trying to walk against the sliding is like walking against flowing water.