Quantity field +/- sign for deferred revenues not supported.

What causes this issue?

You post a document with a revenue item that is relevant for time-based
deferred revenues and has a plus/minus sign for the quantity
(DFKKOPK-SQUAN). This combination is not supported.

System Response

The document cannot be posted.

How to fix this error?

If time-based deferred revenues are used, the plus/minus sign for the
quantity of a revenue item cannot be filled. The quantity plus/minus
sign always results from the revenue item amount.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.