P: Soft Proofing then cropping can result in a blank work area.

Hi...new here and not overlay technical in knowing how to describe but here goes:  in LR when I go to 'develop' and cropping...using the overlay tool and cropping the image makes it totally disappear from the 'proof preview'.  I then have to click on the original pic and back to the cropped picture where I can see it in the lower frame windows (small on the bottom) and it will reappaear in the proof preview for me.  This is new in the last month.  Previously when I would crop, it would simply do that in the proof area and be visible throughout the editing process for me.  I wondered if there is a glitch or if I have inadvertantly changed a setting (hoping not).  Anyone recognize this issue?  Help?