How To Fix WD509 - Method '&' has dialog but task '&' is running in background

SAP Error Message - Details

• Message type: E = Error

• Message class: WD - Workflow definition

• Message number: 509

• Message text: Method '&' has dialog but task '&' is running in background

What causes this issue?

For task &v2& the indicator <LS>background processing</> is set.
Therefore, no methods with dialog may be entered as before-, secondary
or after methods.
However, the method &v1& has dialog.

System Response

A method with dialog cannot be entered.

How to fix this error?

Please select a method WITHOUT dialog.

Error message extract from SAP system. Copyright SAP SE.