Condition record exists, but has not been set

This message tells you that the condition record exists, but has not
been set in the document. If pricing was carried out again for the
document item, then the condition would be set.

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

There are different reasons for this:
The condition was deleted manually in the item condition screen.
The condition record was created later. Please note that order
processing and pricing have buffer mechanisms. This means that a newly
added condition record might only be found after order processing has
been left completely and then started again.
If the condition type is used for subsequent settlement (rebate), there
may be subsequent updating of business volume (the agreement is is
created retrospectively). The document conditions do not contain the
condition record, as the condition record was not created when pricing
was carried out. Updating of business volume is carried out using
special functions for subsequent settlement.
When an item was added, the condition record was accessed with key
fields other than change time. This could lead to different results in
the requirements check at the time of adding and the change time. This
can occur when modifications are made.
In billing (or when copying orders): Certain condition types were not
determined in the source document (this is usually controlled by the
pricing requirements). When creating the document, the document flow
(TVCPF,TVCPA) is processed using a pricing type that does not
redetermine these condition types, although they are supposed to be
called via the requirements.

Error message extract from SAP system. Copyright SAP SE.