How To Fix WL382 - Expression '&' for task: Error during evaluation or incorrect data type

SAP Error Message - Details

• Message type: E = Error

• Message class: WL - Workflow: run-time messages

• Message number: 382

• Message text: Expression '&' for task: Error during evaluation or incorrect data type

What causes this issue?

Expression '&V1&' should return a task for Workflow step no. &V4&.
However, the result does not have the correct data type or returns
errors during the evaluation:
Expression:,,'&V1&'
Value:,,,,'&V2&'
ABAP type:,,'&V3&'

System Response

The Workflow was stopped and given an error status.

How to fix this error?

Please correct the definition or implementation of the expression to
return a value with reference to the DDIC domain HROBJEC_14 (ABAP type:
C14) liefert. You should note that numbers alone may not be used
because they must be preceded by an org. object type "T ...", "WF...",
etc.
Multi-line elements and object references are also not possible at this
point.
A workflow which has been stopped can be continued by selecting the
function <LS>Restart after error</>.

Error message extract from SAP system. Copyright SAP SE.