Reported on IRC at http://chatlogs.musicbrainz.org/musicbrainz/2013/2013-05/2013-05-11.html#T15-42-10-187273

Edits which are expiring show "in x days", "in x hours", "in x minutes". You would expect that if it's expiring in less than a day, it would show "in x hours", but it seems this only works if the edit is expiring on the same day. Presumably if you enter an edit shortly after midnight UTC, it will never show "in x hours", it will just suddenly switch from saying "in 1 day" to "in x minutes".

https://beta.musicbrainz.org/search/edits?auto_edit_filter=&order=asc&negation=0&combinator=and&conditions.0.field=open_time&conditions.0.operator=BETWEEN&conditions.0.args.0=2013-05-04+23%3A59&conditions.0.args.1=2013-05-05+00%3A05&conditions.1.field=status&conditions.1.operator=%3D&conditions.1.args=1&field=Bitte+w%C3%A4hle+eine+Bedingung is an example edit search for edits expiring today which (at the time I'm writing this) suddenly switches from "in 8 hours" to "in 1 day" even though the difference between the edits is only 5 minutes.