One of these bugs is in the File History utility – something that first appeared in Windows 8. The issue I encountered was that the option to exclude folders, although Windows 10 appears to accept the new configuration to exclude certain folders I specify, simply doesn’t work. File History continues to store those folders on the backup drive. In my case, there are some very large folders which I back up to a separate external drive (i.e., music/mp3 files and photos), which within a couple of days completely fills up primary external backup drive.
I haven’t yet found a workaround for this problem. A search at Microsoft reveals that this is not an isolated issue; indeed, there are other problems noted with File History suggesting that it is not yet a reliable backup strategy – see this answers.microsoft.com search. In particular, see this post, which to date has no replies.
For now, my solution was to turn off File History entirely until either I can find a fix or workaround, or Microsoft fixes the problem.