It is very odd. Fai is the established pronunciation. I guess some people (who had probably never heard other people pronounce in the normal way) thought that, since it was a letter like b, c, d, etc, it should rhyme with those and it caught on among other people who were unaware of the established pronunciation. Some people also pronounce xi as ksee which sounds a lot like c. They never pronounce pi as pee though.146.199.171.10613:06, 20 November 2021 (UTC)Reply
1963,Psychology Through Experiment (George Humphrey, Jaroslav Antonio Deutsch), page 90:
[…] tolerance (Frenkel-Brunswik 1949) for it showed that those persons with the strongest defences against internal conflict, i.e. obsessionals and conversion hysterics, were those least able to perceive the reality-conflicting phenomenon ofphi.
