@George I am going to delete this bug report. Problem was actually some parameters Wappler auto created from calculations in the Library action. After I removed those $PARAM items and opened the EXEC step everything worrked.
Wappler sometimes create additional items in $PARAM variables automatically based on calculations one does in add/update server actions.
The highlighted item is an example of one of these. There was another one that I removed that broke the EXEC step so it dit not show my parameters at all.
That highlighted one was added by Wappler automatically - not by me.
Recently I have started doing my calculations in set value actions and not inside the add/update db step which prevents this from happening.