Behavior:
When attempting to export a Preconfigured Solution, the following error is shown:
"Preconfigured solution could not be exported. 'Cannot export workflow because there is an user assignment in activity'"
Solution:
When exporting Preconfigured Solutions, this error will occur if "user assignments" are present within a workflow. To successfully export the Preconfigured Solution, please replace all user assignments with "user workflow variables" or remove them altogether.
KBA is applicable for both Cloud and On-premise Organizations.