Given that there is no Japanese record of this B-29, 42-65273 crashing on land it is more likely this plane was either damaged by Japanese AA artillery or enemy aircraft or experience mechanical difficulty causing it to ditch/crash at sea somewhere between Japan and Tinian.
The exact reason for the loss of this aircraft is likely never to be known.
Here are the Findagrave memorials for this crew with content added by me.
Major John Bratton DuBose, Jr. (AC) O-421743, MIA/KIA
https://www.findagrave.com/memorial/...bratton-dubose
https://www.findagrave.com/memorial/...john-b-du_bose
2nd Lt Lois Franklin Beard, Jr. (P) O-937616, MIA/KIA
https://www.findagrave.com/memorial/...6/lois-f-beard
2nd Lt William “Buck” C Powell, Jr. (N) O-2079095, MIA/KIA
https://www.findagrave.com/memorial/...m-clyde-powell
F/O Howard R George (B) T-136546, MIA/KIA
https://www.findagrave.com/memorial/...-robert-george
Sgt Harold W McWilliams (FE) 37662942, MIA/KIA
https://www.findagrave.com/memorial/...d-w-mcwilliams
2nd Lt John F Flynn, Jr (Radar) O-2076611, MIA/KIA
https://www.findagrave.com/memorial/...8/john-f-flynn
Sgt Alfred B Nowlin (RO) 16189701, MIA/KIA
https://www.findagrave.com/memorial/...d-bruce-nowlin
Sgt Ivan D Barker (CFC) 36902696, MIA/KIA
https://www.findagrave.com/memorial/...an-dale-barker
https://www.findagrave.com/memorial/...an-dale-barker
Cpl Curtis L Meadows (RG) 35903173, MIA/KIA
https://www.findagrave.com/memorial/...s-loyd-meadows
Cpl Harry R Anderson (LG) 19179062, MIA/KIA
https://www.findagrave.com/memorial/...dolph-anderson
Cpl Leon R Weber (TG) 13159057, MIA/KIA
https://www.findagrave.com/memorial/...6/leon-r-weber
https://www.findagrave.com/memorial/...-r-weber/photo