The
Kriegsmarine Operations Staff War Diary includes this item:
9 October 1944
In St. Nazaire, superior FFI units were beaten back. At 0745. An "He 115" plane with medical equipment, submarine spare parts and a General Staff Officer for the Fortress La Rochelle has landed. It has been provided to continue the flight to La Rochelle on the morning of 10 Oct.
(That is the postwar translation available at
https://archive.org/details/wardiarygermann621944germ
ULTRA briefly mentions a number of other He 115 flights from Friedrichshafen to the Atlantic "fortresses" in the period October 1944–January 1945.