Since a couple of days ago DeathNotes has stopped recognising the {owner} of turrets, gun traps etc. Can anyone else verify this?

It's said that for a while if it's a raidable base. If you have that plugin, that could be your issue. I run a PVE server, so we don't normally get player trap notifications.

Until a couple of days ago it used to say "unknown owner" for raidable bases. Strange. You are right though, I've tested with normal base and that's fine.