Similar irregularities exist in Standard German (e.g. "Ich steige Stefansplatz aus", "I get off [at] Stefansplatz", when say driving the bus), and there's a whole sociolect that regularises it to also say "I'm going school". And, no, the "that noun is an adjective now" explanation doesn't really work in German.

Understanding those kinds of (usually informal) uses is trivial if you know the language, it's using them like a native that's difficult. Forget studying grammar they need to be learned by osmosis. Grammars linguists produce, even highly detailed ones, have a very hard time capturing the possibilities, what's acceptable when playing around with the language.