Steps to reproduce:
- find a page that has been recently deleted
- add it to watchlist
- open watchlist
There should be a deletion log record, but there isn't. Reported and verified on Hungarian Wikipedia (the first reports go back to October 2010); does not seem to affect the English Wikipedia. Based on the timing of the first reports, it might be FlagRev-related (appeared a couple days after the big FlagRev code update).
See Also: T35591