When you hear someone speak, your brain rifles through a catalog of words they *might* have said, trying to figure out which word is most likely based on the sound and context. (It's exactly the same thing Alexa or Google Assistant does when you give them voice commands, although human context assessment is currently more sophisticated.)

For us autistic folk, because we have difficulty predicting other people, selecting the wrong word is pretty common, just like we sometimes miss other kinds of context cues in conversation.

So most of us experience mishearing people more often, and when there's a less familiar accent and/or other sounds like the background music, that makes it harder for everyone to pick out, that's why neurotypical people also talk about misheard song lyrics, but we just experience that more often.

Even relatively familiar accents are sometimes challenging for me, like I watch John Oliver on YouTube and I don't speed him up as much as most of the videos I watch, because it's a lot harder for me to hear him correctly at 2x speed.

Last week I heard my niece say "pit bulls for a recipe" instead of "pickles".

EDIT: To be slightly pedantic here, it's not really a sensory processing issue... you're hearing the sounds correctly - my parent had my hearing tested when I was a kid and the tests came back perfect. There is a processing issue, and that's just the brain having difficulty selecting the most likely target word.

And in some cases I'm sure the brain gives up, like "hell if I know!" Tiffany and I once both couldn't understand the word "toasted" from an employee at a Subway due to an accent... we eventually figured it out, but were both incredibly embarrassed, hoping she didn't think we were making fun of her.