There is no explanation until now, it was found on Pilot Mt.:
http://www.etherit.co.uk/month/thismonth/10.htm
February 10th, 1944 (THURSDAY)
GERMANY:
U-872, U-1009, U-1203 commissioned.
U-880, U-1303 launched.
SPAIN: U-193 arrived in El Ferrol for repairs.
BURMA: Japanese troops take the Ngakyedauk Pass, cutting off the 7th Indian Division at Sinzweya.
The 1/7th Gurkhas fighting for “Bare Patch” move around the Japanese flank and by 2.20pm the Japanese, now denied water and almost completely surrounded, begin pulling out. Just over an hour later, the position is clear of Japanese. (Daily Telegraph, 21.10.2003, p.27)
NEW GUINEA: Australians from Sio link up with the Americans near Saidor.
CAROLINE ISLANDS: Japanese naval forces abandon Truk.
PACIFIC OCEAN:
Submarine USS Spearfish torpedoes and damages the Japanese transport ship Tatsuwa Maru (6345 BRT) SW of Formosa in position 21.53N, 119.13E.
Submarine USS Pogy torpedoes and sinks destroyer Minekaze and Malta Maru some 85 miles NNE of Formosa in position 23.12N, 121.30E.
CANADA: Frigate HMCS Antigonish launched Esquimalt, British Columbia.
U.S.A.: USS YMS-428 laid down.
Minesweeper USS Pochard laid down.
Minesweeper USS Caution commissioned.
USS PC-1180 commissioned.
ATLANTIC OCEAN: U-545 Kl. IXC/40 is Scuttled west of the Hebrides, in position 58.17N, 13.22W, after crippling damage from 4 depth charges dropped by a British Wellington aircraft (Sqdn. 612/O). 1 dead and 56 survivors.
U-666 Kl.VIIC Listed as missing in the North Atlantic. There is no explanation for its loss. 51 dead (all hands lost).
[U-545 was in fact attacked by two aircraft. The other one, a Canadian Wellington (Sqdn 407), was shot down during the attack.
The survivors were picked up by U-714 after a while and taken to St. Nazaire, France. Kptlt. Mannesmann then commanded U-2502. He died in an air raid on Hamburg on 8 April, 1945]
(Alex Gordon)
There is no explanation until now, it was found on Pilot Mt.: