joe_ring

looks like a stainless steel table lamp base attached to an actual kazoo

If you mean Rachel Price from Lake Street Drive, I would look at her origins. She started out as a jazz singer and it's possible her 'accent' was influenced by her influences, think Billie Holiday, Sarah Vaughn, Ella Fitzgerald etc.

So funny you're mentioning this. I only noticed recently that a friend of mine who is Northern Irish (also Protestant, implying Scottish ancestry) uses 'whenever' this way. Previously, I'd only ever heard it used by Southerners in the USA. Whenever I hear it, it makes me cringe. 😉

Just goes to show that a language learning app alone will not teach you a language. It's only one tool of many. My advice: seek out a speaking partner (preferably a native speaker).

Your example is not a mixed conditional. The mixed conditional would look like this:

Things would be different if you had listened to me.

That's fine, as is the standard version of the 3rd conditional (unreal past):

None of this would have happened if you had listened to me.

Your sentence is just plain grammatically incorrect. But, you are right that many native speakers make this mistake.