Unexpected metatag values when overriding metatags via panels

Overriding values using metatag_panels with a default view causes other metatag values to change. I've noticed this when I've had duplicate tag values, on different metatags even though they weren't changed through the overrides.

I've traced it to a scoping issue with the use of a reference variable, which causes all the tags to be "reset" on a later loop using the same variable name.