The Grids Lines have Disappeared

The grids lines have disappeared from my plan after waiting 4 minutes for my project to open up. There is a yellow triangle along the bottom with the statement " Annotation for Grid "" E1431 "" was deleted from model "" Foundation plan "" because the grid definiation could not be found ".

The grids were there 5 minutes before. After exiting OB CE U5, the grids return but not looking like they were , so I end up having to adjust them once again.

this problem isnt jsut happening with myself at my work , we have 2 other users that this has happened to.

Is this a known problem?