Collection says there are 10 resources in it, but where are they?

I got into this bogus state by opening my "Topical Bible Indexes" collection and adding "OR mytag:topical" to its rule. It was already showing only one title even before I made that change, as I recall.
Log file: 6683.MissingResources.zip
Forcing a refresh (closing and re-opening Logos) fixed it. But how did it get that way in the first place? I hadn't done much in that session. Hopefully the log file will contain some clues.