Skills change their mapping on utility bar without change being made by the player.
Just started this patch
It happens for me playing Rev, Shiro utilities. Specifically phase traversal and impossible odds. Happens in the middle of a PVP match when you can not change this yourself, also when waypointing or zoning new pvp map or to pvp area every single time. I have not see if this happens in the open world part of the game or WVW