From Philippines 1940 to Italy. Blocked, then forwarded

[ZavattoniP]

Hello
I must say that WWII isn’t my field, nevertheless I’m fond of odd covers like the following one.
Sent from Manila on May 6 (or 16), 1940 to Italy it goes via Singapore (censorship) and Egypt (again censored) where it was blocked because Italy had entered the war against England on June,10 1940. The cover was sent back (however without any indication) but remained in Singapore at the Dead Letter Office. Nevertheless it arrived in Milan on 19 October 1940. The month and year are not that clear, but the postmark clearly shows the year of the "fascist era": XVIII [eighteenth]. Since the years of the "fascist era" began on October 28, 1922 (the day of the March on Rome and Mussolini's seizure of power), the year XVIII ended on October 21, 1940.
How was this possible?