The scale in and sliding popups effects clash (Martin's words!). Reproducible: Always Steps to Reproduce: 1. Enable scale in effect 2. Hit F12 (to show yakuake terminal) Actual Results: Yakuake appears using the scale in effect Expected Results: Yakuake slides in from the top I can test patches. After I'm back from my way too long retreat to a tropical island.
Created attachment 79745 [details] Striptease for KWin (not my own words) qdbus org.kde.kwin /KWin supportInformation > /tmp/kwin-striptease.log
This would happen when scalein was run before slidingpopups, but since yakuake sets/withdraws the property to call kwin for sliding (compared to it's own animation) at runtime, i'd rather bet for https://git.reviewboard.kde.org/r/107983/ If you successfully survived your castaway, please see whether you've that patch (wasn't upstream when you reported) in kwin and whether the problem still exists despite.
Fixed by https://phabricator.kde.org/R108:fb69b791a16f4a89fd79a010ce8f67419de16004