Process Maintenance is fickle at best. Go into MES in Customization mode and click the button you should get a little box that shows Calling Program, Called Menu etc…
Does that show UDMES2? or does it just show Erp.UI.RcptToInvEntry.dll
If it shows the DLL and not the menu you may ahve to replace the button.
Issue:
In E10.1 MES, a Cloud Multi-Tenent (MT) Customer can create a Customization for a MES Button that calls a Base Form, like Work Queue. However, since a Cloud MT Customer can’t deploy a Customization to a Base Menu, how does a Cloud MT Customer deploy this Work Queue Customization?
Resolution:
In Menu Maintenance, select the Base Work Queue Menu from the Tree. Then select Actions > Copy to Current Company. This creates a copy of the Work Queue Menu, however, the Module will be UD and the Owning Company will be that of the current Cloud MT Company. In the Customization field, select the drop down list and then the Customization. Save the Changes. The next time MES runs, the Work Queue Customizatoin will display.