When in gamemode 3 (spectator mode) the player when at a very slow speed, a speed which can't really be recorded easily, would when intersecting blocks (from for example a horizontal corner) be narrowly pushed around the block, as if they were in any gamemode but spectator, like survival. Basically the same block to player behaviour, except at slow speed. For example it's just a number, which should be at 0, like the players interaction with blocks. in /gamemode 3 it's at 1 of 100, and any other gamemode 100 of 100. Or rather the speed.

This although is a small bug, should addressed

Has only happened in the overworld, cannot it occurs in the nether, or end.