>>23172992as a certified ESL myself I can tell you that native speakers are much more likely to make this particular kind mistake.
When learning English as a second language in school, you're gonna encounter "should have" or "should've" more often written down than spoken out loud at first.
They're also gonna explicitly learn about the available auxiliary verbs in English instead of having to intuit it from having heard it a bunch as a baby.
Native speakers try to mach words to the sounds they make when they write, but with a second language you're gonna start out with trying to pronounce written words.
An ESL that didn't do his reps properly will make other kinds of mistakes.
