http://www.gamesas.com/topic/1352954-unofficial-creation-kit-modding-bug-list-3/page__view__findpost__p__20535663
Fixed at some point.
http://www.gamesas.com/topic/1352954-unofficial-creation-kit-modding-bug-list-3/page__view__findpost__p__20581346
Reporting again because this one was due to user error and not an actual bug.
http://www.gamesas.com/topic/1352954-unofficial-creation-kit-modding-bug-list-3/page__view__findpost__p__20622868
http://www.gamesas.com/topic/1355027-speech-actor-value-not-working-in-perk-entries/
These two are actually the same bug, sadly not fixed yet though.
Skyrim.esm is full of errors. While these are harmless, it can make genuine errors from your own plugins difficult to spot.
As of CK 1.6.89, I think this one is safe to drop as the initial batch of errors has been reduced to almost a single screen in a text editor. I doubt very much every possible error source will ever be removed, but it's easy to spot stuff caused by your own mod now.
http://www.gamesas.com/topic/1345715-unofficial-creation-kit-bug-list/page__view__findpost__p__20289422
Appears to be fixed. The camera is sticking to the point of the last object to be deleted, and I just axed most of a dungeon testing this one.
http://www.gamesas.com/topic/1345715-unofficial-creation-kit-bug-list/page__view__findpost__p__20290971
Appears to be fixed as well, sorting in either direction on the landscape editing window displays all available texture choices.
http://www.gamesas.com/topic/1345715-unofficial-creation-kit-bug-list/page__view__findpost__p__20291390
Fixed at some point, column headers have been maintaining their widths for as long as I can remember. Perhaps 1.5.24 got this one.
http://www.gamesas.com/topic/1347249-unofficial-creation-kit-bug-list-2/page__view__findpost__p__20312595
I'm a boob and didn't realize that was solved via the "general subtitles" option at the time.
http://www.gamesas.com/topic/1352954-unofficial-creation-kit-modding-bug-list-3/page__view__findpost__p__20430873
Appears to have been fixed, assuming I'm looking in the right place.