Action cards in Kanban cannot be moved by drag-and-drop after update to 9.3.1

Good morning,

we are using Kanban boards with action cards to handle our open topics.
After updating from 9.1.3 to 9.3.1 we receive an error message after trying to move cards by drag-and-drop from any slot to the other (see attached picture and log message).

Screenshot: 
 

Log:2021-10-13 08:16:04.113 ***** ERROR ***** [V9.3.1] ERROR *****
2021-10-13 08:16:04.113 ***** ERROR ***** [V9.3.1] on file '/var/www/html/tool/kanbanUpdate.php' at line (152)
2021-10-13 08:16:04.113 ***** ERROR ***** [V9.3.1] cause = Undefined variable: elmtRequired

Thank you in advance for your help!

Best regards
Bernd 

Hi babynus,

thank you for your quick reply!

Is there a quick fix or do we have to wait for the next release?