Problem Uploading ebooks to Samsung Galaxy Tab S7FE with Calibre 5.42

I've been using Calibre 64bit for several years and have never had a problem with it. I just 'upgraded' from 5.40 to 4.42 and tried to upload a few new epub documents to my device. The upload went entirely as expected, except that when it finished quite normally according to the messages in the jobs dialog (Upload books to device, Send metadata to device), the books are not on the device, and they show in the Calibre main window as not on the device.

I have done the usual--rebooted my computers (this problem occurs with both Windows 10 and Windows 11), restarted Calibre, uploaded files to the directories where my epub documents are stored using File Explorer, deleting the two Calibre metadata files and allowing Calibre to recreate them, all apparently successfully, but Calibre 5.42 resolutely refused to upload, even though it tells me it has done so.

I'll stress that this tablet and an older Samsung Galaxy Tab A have worked fine with Calibre up until this point. I upload documents almost every day.

I am hoping that there's a solution to this problem. In the interim, I am going to try downgrading to Calibre 5.40 (the last version that worked for me) if I can find it.

I wonder if I am the only one seeing this problem, and if so, what I can do about it.