This morning I got up and checked my stats, WUProp hours looked VERY low for overnight. Looked at a host, WUProp was not on it! Checked logs, found that BAM had detached the project (they switched from http to https recently, so far so good) but had not reattached it!

This had happened on several hosts; all those using BAM?

Disabled BAM and manually attached WUProp. Have screen dumps of messages on a couple of the hosts. Luckily was not using BAM on any of the hosts that require non-default project preferences as BAM wipes those out...

Not sure if this applies to you or not Bill, but apparently not all hosts are able to use the "https" url. This is the latest news from WUProp:

Nope - Windows 10, latest (or next to latest) BOINC, BAM handled the Collatz move just fine... no clue. Although WUProp has "switched back and forth" a few times trying to get the details right. It's running fine now on HTTPS, anyway, with manual attach.

I had that issue too. Usually BAM is good about reattaching although not this time for some reason, but IIRC, I think I just manually resynced BAM and it reattached. Failing that, a global detach and then a global reattach, then next auto-update BAM should resync.

What does the manager log say?