After updating from 2.2.0 to 2.2.2 track lengths are not shown anymore in the playlist. They are all shown as 0:00. media-libs/taglib was also updated to 1.6.1-r1, with use flags +asf, +mp4 (as needed). Maybe the something is wrong with taglib?
Ok, it's a known bug from Amarok 2.2.1:
Reported as "FIXED" upstream, but it's only a workaround to me... and wasn't fixed in 2.2.2. It just requires to "Fully rescan collection". In my opinion this operation should be done automatically upon upgrade. Should I file another bug report upstream?
They did add a new button to fully rescan the collection.
You may try to open another upstream bug, but I'd expect it to be closed as a dupe. If something changes, feel free to reopen the bug.
Ok, filed upstream: https://bugs.kde.org/show_bug.cgi?id=225117