Object key values invalid (internal syntax error)

What causes this issue?

The object key has the following invalid value:
&V1& &V2& &V3&
Only the following is valid:
R3TR TABU xxxxx
xxxxx may not consist solely of blanks.

System Response

The function terminates.

How to fix this error?

The invalid fields cannot be changed directly with a transaction. The
relevant request/task therefore can no longer be used. Perform the
following 5 steps:
Start the Transport Organizer (extended view) (Transaction SE01).
Manually transfer all the objects and their keys to a new request
Caution:
Do not use the function <LS>Include</>. This function also copies the
errors.
Delete the locked entries of the old request/task.
Repeat the function with the new request/task.
If the error occurs again, inform the SAP hotline.

Error message extract from SAP system. Copyright SAP SE.