Anyone else had this issue?

When I have done splitting a polygon using in FEFLOW standard, I use the mouse wheel to zoom the viewpoint. BOOM! The background map suddenly disappears. At first I thought the map is just gone, but when I zoom out far enough, i find the map somehow shift way from the polygon. That's not I expected! From my past experience, this happens ramdomly, so I guess it is a BUG.

Anyone sharing some thought on this is appreciated.