The moving Strength boulder curiosity occurs in Pokémon Emerald.
DetailsThis is likely not a glitch, but an interesting mechanic that prevents something that would possibly trap the player forcing them to start a new game. In the fourth Trick House puzzle of Pokémon Emerald is a boulder puzzle.
Luckytyphlosion suggested that there would be a way to trap yourself in the room by moving the boulders in a certain way, such that the player is surrounded by two pairs of boulders completely adjacent to each other that cannot be pushed, and a boulder that cannot be pushed because it is next to a wall directly to the west and north of it.
Luckytyphlosion demonstrated how to do this with the steps in this thread.
In actuality, taking Luckytyphlosion's route has the game reset the bottom-left boulder of the room, allowing the player not to be trapped.
Specifically, the bottom-left boulder in the room resets to its original position after the player takes ten steps or more above it.
A route to try and trap the player in Japanese Emerald (where the map of the room is different) is not known, however, the position of the bottom-left most boulder also resets in Japanese Emerald after taking ten steps above it.
Making a step north from one of these imaginary boundaries will cause the bottom-left boulder's position to reset.