I just ran into the following bug:

I have a logbook where entries have several attributes, among which several dates. All of these are set to "Type <attr> = date". If I use the "Select" action, tag several entries and subsequently chose "Edit", the values of all date attributes are wiped. All other attributes are kept at their original values, unless changed explicitly. For the date entries, the date choosers are shown (as when editing a single entry), but all set to blank.

Editing single entries works fine.