After a lot of investigation, it seems this is caused by Compiz' default Edge Flipping binding to the top of the screen under Desktop Wall -> Bindings -> Edge Flipping. Changing Top to None resolves this.
After a lot of investigation, it seems this is caused by Compiz' default Edge Flipping binding to the top of the screen under Desktop Wall -> Bindings -> Edge Flipping. Changing Top to None resolves this.