ok, makes sense. the mossies sadly an example of friendly fire (looks like 2 different ones to me). doing a little research it seems that it was pretty much open season on mossies for the 4FG. especially surprising for this pilot as a member of 335FS because they had converted from 121 (Eagle) Squadron RAF so should have had a pretty good idea what RAF aircraft looked like. (although I dont believe 2nd Lt Lewis flew with 121sqn, must have joined later)
cant find out where 335FS were flying on 6/10/1944, but heres the mossie losses for that day:
ML996 Mosquito B.XVI 105s Dortmund Lost without trace from intruder mission
MM113 Mosquito B.XVI 571s Berlin Abandoned over target-area during intruder mission
HR193 Mosquito FB.VI 107s Osnabrück Failed to return from intruder mission
NS522 Mosquito PR.XVI 140s Friesische Inseln Failed to return from reconnaissance
HK179 Mosquito XII 307s Coltishall Swung on take-off and hit parked Tempests
HK499 Mosquito XIII 29s Handorf Failed to return from intruder mission
HK504 Mosquito XIII 29s Stade Failed to return from intruder mission
HK503 Mosquito XIII 409s Le Culot Bellylanded due to engine failure during sweep
MM574 Mosquito XIII 409s Bruxelles Damaged by débris from Ju-188; engine cut and abandoned

Thomas and Shores ("2nd Tactical Air Force") say it was the 140 Squadron machine, F/L A.E. Palmer and F/S D. Gardner both killed. Four days earlier, another 140 Squadron aircraft had been shot down by Thunderbolts.
So far as I can determine, 140 lost one crew to German flak, and possibly another to a 262, with third aircraft being damaged by the Luftwaffe but returning safely.