Where does “変換ミス” come from?

変換ミス (Japanese) comes from Japanese ミス, from English mistake, from Middle English mistaken, from Old Norse mistaka — to take in error, to miscarry.

Ancestry of “変換ミス”, step by step

変換ミス traces back through two separate lines of ancestry.

via Japanese ミス

StepLanguageWordMeaning
1Japaneseミスmistake, error; make a mistake; Miss
2EnglishmistakeTo understand wrongly, taking one thing or person...
3Middle Englishmistaken—
4Old Norsemistakato take in error, to miscarry

via Japanese 変換

StepLanguageWordMeaning
1Japanese変換conversion, change
Every word from Old Norse mistaka →Every word from Middle English mistaken →Every word from English mistake →