Yes, I've come across this. It's very confusing for me. Not sure if it's because I'm not a native English speaker or some other reason but it always makes me pause and is not always clear which way it's meant.
https://en.wikipedia.org/wiki/Rising_declarative
The older generations think that this is “wrong”, so they don’t teach you what it means or how to use it.
Just an observation—foreign language education generally teaches a formal version of the language and neglects informal/casual usage. This is normal. The problem is that informal/casual usage today becomes formal usage in the future, as language changes.
Just as an example, if you take a Japanese class, they’ll probably teach you 「おはようございむす」 but not 「おっす」 (good morning), 「ありがとう」 but not 「サンキュー」 (thank you), and teach you to say 「無理」 when you should say 「難しい」 (impossible).