Comment 102 for bug 1890791

(In reply to sramey40 from comment #91)
> Note: On my video attachment, it is encoded as h265 so it won't play in most
> browsers. Download it to watch.

Thanks it shed some light on the case you are talking about: moving/copying files to sub-folders of the current folder, and that folder state doesn't get refreshed.

This bug sort of reported the same issue, and I fixed it, fixing your case as well:
https://bugs.kde.org/show_bug.cgi?id=440712

https://invent.kde.org/frameworks/kio/-/commit/8b515e3827fa464384ae142cce493e9a97351c5b

I am backporting it, to next KF5 version.
https://invent.kde.org/frameworks/kio/-/merge_requests/1409

It does not solve the case when you move files from the command line though.