String::getIntValue creates inconsistent result

I encountered a bug in my app that was happening on my machine, but not on my colleague’s machine. When attempting to convert a String object with text “1” to the integer 1 using getIntValue, it returned 0 on my machine, but 1 on his. 2+ returns correct on both machines, so it’s just an issue with 1 as far as I know.

The only obvious difference between our Macs is mine is Silicon while his is Intel. Any other M1 users get an incorrect result?