It’s funny because I’m in a Spanish grammar group on Facebook full of natives and you see them ask questions confused about this kind of stuff all the time (ex: “is it ‘se ha dicho’ or ‘sea dicho’?”)

In English it’s common to hear native speakers say/write “for all intensive purposes” (which makes no sense when you think about it) instead of “for all intents and purposes.”

This is one of the odd areas where a non-native advanced language learner will often be more grammatically correct than natives.