If you open the Workflow Manual Activity
Properties, you will find "Constraints" listed as checkbox. (Refer to the image at the bottom)
These options are to constrain what the user can and cannot do while performing the Workflow Activity
.
Deny items to be added/removed: Prohibits the user from adding or removing items in the Process.
Deny Subject(s) to be edited: Prohibits the user from editing content items associated with the Activity.
- Deny Bundle metadata to be edited: Prohibits the user from editing the metadata of a Bundle associated with the Activity.
Please check the Constraints for your Activity in Visio Workflow Definition
. I think, you need to uncheck one of the two (Deny Subject(s) to be edited OR Deny Bundle metadata to be edited) and save the Workflow Process Definition
in Tridion.