This is an error in Rohwer. It is a rather complicated story:

He wrote that she was mined on RORQUAL's minefield (laid actually on 22.03.1943) from a deduction that an ULTRA signal had reported that CARBONELLO was torpedoed and beached on 5 April 1943 (see DEFE3/808 frames 556-557).

In fact, the ULTRA decrypt had mistaken REGINA for CARBONELLO (HMS UNBROKEN had torpedoed REGINA on 04.04.1943). CARBONELLO was not at all involved in this convoy. She was travelling from Brindisi to Crotone on that date and recorded no incident.

In August 1943, CARBONELLO was indeed plying the waters between Olbia, La Maddalena and Civitavecchia (where she was seized by the Germans at the Armistice).

Platon