Please see the attached video - it may make the bug much clearer (youtube link: https://youtu.be/nuVrWIkWE_4)

I've tested this bug with 1.15.2, and 1.16-pre1 and this bug seems to be present in those versions.

If you collide with a wall with left/right on the +/- Z axis, your horizontal velocity doesn't seem to be reset when running into blocks.

To reproduce this bug, I positioned myself such that when I held right, I'd be colliding into the wall. In the video, the positive yaw value reflects that (for the first segment). I also hold W to push myself up against the wall. This doesn't seem to work for +/- X axis in my testing.