v4.1 not returning properly

[Yen]

I have a function that sorts through strings and returns an array containing the ones with the highest value (two or more may share the highest value).
However, it always returns '0' when it's called on someone using v4.1.
I debugged them, and everything went properly. The end result, which should have been returned, was the proper string. However, like I said, 0 was returned.

Is there any way around this?