Browsing photos v2019.5 arrangement

When browsing in 2019.5 with grouping RAW+jpg off the display of thumbs does not fully change to RAW and separate jpg next to it. Some do but most don't. I didn't have problem in previous version. How can I get them to display properly or is this a bug?

edit: I think I found the reason. I was sorting on capture date. When sorting on file name they are sorted properly.  Going back to by date I found that some of the photos had not imported the date metadata so when I manually imported metadata they sorted correctly.  I import to my computer with another app but work with files in On1. Bug in importing dates? Other fields seemed to be ok.