I just ran a RSPro RC Font scan only (for speed). As soon as I checked "don't show again," True changed to False in ...\Settings\RegCleaner.dat.
Upon repeating the scan -- no report.
When I change False to True with notepad and do the scan again -- the report is back.
So I'm not having a bug there.
There is this small bug: if you rescan after changing False to True but without closing the tool window, the scan window shows with the "don't show" box already checked. If you don't uncheck it, closing the scan report will change the True to False.
Of course, the workaround for this small bug is uncheck the box before closing the scan report. :)