Lightroom Classic CC 7.2: keyword list counts wrong

I am re-organising my keywords, specifically moving keywords from within a hierarchy to root-level keywords. Because of the difficulty of dragging an entry up or down the very long tree I am using the following process.

1. Click arrow alongside keyword to move
2. Select all matched images
3. Create new simple keyword choosing "Add to selected images"
4. Un-check check box to left of original keyword to remove from images, grid updates to show no matches

After doing this the count next to the original keyword should become 0 but this does not always happen.



In the screenshot above, having worked through the four keywords under "locations" in this manner, I would expect them all to show 0 but only two of them do.

Clicking on the arrow to right of "beach" or "street" shows no matching images but attempting to delete them warns that they will be removed from 57 and 2 photos respectively.

The post Lightroom: Incorrect keyword list count from 5 years ago has an answer that explains this can be caused by implicit assignment of child keywords but that does not seem to be the cause in this case as the drill-down arrowheads are dimmed, indicating that none of these keywords has any children. I am at a loss to understand why this is happening only in some cases but not others.

I believe that deleting these keywords will not actually remove them from any photos and if even they do it is not a big issue for me, so I am going to go ahead and do that. However I thought I should report this as it may be a bug and if it is not, perhaps someone can explain the behaviour to me.

This is happening in Lightroom Classic CC 7.2 on Windows 10. I have not done similar re-organisation in previous versions so can't say whether this behaviour is new to 7.2 or not.