@sunflowerinrain my best guess is than the man/men distinction is easier to remember because changing the vowel changes its pronunciation. For some reason, in the woman/women distinction, the orthographic change is on the second vowel but the pronunciation change is on the first.
@khird Ah, depends how clearly you pronounce the second syllable, I suppose. I make a distinction between -man and -men. The first syllable certainly has a more evident change, though.
I'm still not sure why it's typed incorrectly, nor why it defaults to -men. Perhaps it's an autocucumber problem.