Found a stray (1) on a newsgroup today, after reading all the messages:
Refresh doesn't help. There's no filtering.
Nothing in the log:
[DEBUG] 12:06:42.093 | [Usenapp 549570]13943893966209 | Individual | Inputstream | NSStreamEventEndEncountered
[DEBUG] 12:26:42.400 | [Usenapp 549570]15967333626961 | Individual | Inputstream | NSStreamEventEndEncountered
[DEBUG] 12:36:19.914 | [Usenapp 1109727]Files database not found. Creating a new one.
[INFO] 12:36:19.975 | [Usenapp 651796]----------------------------------------------------------------
[INFO] 12:36:19.976 | [Usenapp 651909]Start NNTP_Post Operation for Re: Looking for a skilled OnyX user...
[INFO] 12:36:19.977 | [Usenapp 651996]----------------------------------------------------------------
Restarting fixed it, but thought you might like to know in case there's some count-resync you can add at some other logical point(s) than a restart.