Previously when an application was launched the icon would be underlined and remain in it's (placed) position within the task manager. Now the icon is underlined and moves to the rightmost position, upon closure of the application it returns to it's original position. Further details and screen shots: https://forums.opensuse.org/showthread.php/527592-KDE-Icon-only-task-manager-chase-the-icon (Forked from bug # 385563 as that referred to the "Normal" taskbar)
Same problem after today's update to 5.11.0 on Arch Linux x86_64.
I can add that I tried to set separateLaunchers:false at plasma taskmanager and even though it fixed things after repositioning my tasks, on the next reload of plasma the launchers were put in the start and all the windows (including those that they had a launcher) at the end. So the launchers position becomes broken from a user point view in every plasma relogin.
*** This bug has been marked as a duplicate of bug 385594 ***
For Icons-only Task Manager, you can delete the task manager, create a new one and pin your applications afresh, and after that it seems to work (except that you see an additional icon at end of taskbar for a brief second after launching an application). This doesn't workaround doesn't work on regular Task Manager for me.
Please add any new comments to https://bugs.kde.org/show_bug.cgi?id=385594. The more we centralize information in a single bug report, the faster it gets fixed. Thanks!