SAP Note 28764 - ME31 Source list maintenance from within outline agreement

Symptom:

Under certain circumstances, if the user invoked the function "Back" from within source list maintenance, he or she was liable to be thrown out of the transaction completely instead of being returned to the outline agreement.

Cause and prerequisites

The error occurred only if you branched directly from the item detail
screen into source list maintenance.

Solution
Corrected as of Release 3.0B.

Additional key words

Contrakt, scheduling agreement.