Correct the formula

What causes this issue?

The syntax of the formula is incorrect. The incorrect formula part
is marked with a '?' where possible.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

... &v1& ...

System Response

How to fix this error?

Correct the formula using the notes below:
INCLUDE RW_FORMULA OBJECT DOKU ID TX

Error message extract from SAP system. Copyright SAP SE.