it will happen when you taskswitch around in windows, so alt-tabbing introduces it among other things
a workaround is to be in the control room at 1x TC while taskswitching
a fix is to save-reload
when visiting these forums for example, while the game is running: the best way to keep the game bug-free is by being in the CR in real time when you alt-tab out of the game
don't ask me why
