A bug has snuck into the old web client and the 2023.3 version of Portal 2 when having data grids in the workflow.
If you have upgraded to 2023.3 before October 12th, there is a dirty fix around it as described here:
Within the “local-min-0c8ca18d66.js” file in the “portal session service” folder, do a search for the string “a.indexOf(t)>-1”. This specific string should be replaced with “true;” There should be only a single occurrence of this particular search string. After making this replacement, restarting the Internet Information Services (IIS) may be necessary to ensure the changes take effect. Reloading the portal should then restore the grid’s functionality.