Differing tire sizes on tread and side wall
Looks like an error to me - its either 29" or 27.5" with no ambiguity.   It is unusual to see details embedded in the tread, I've never seen it in person.

You could choose to highlight the correct size details with a white paint pen, and/or file the wrong marking off with some careful strokes of a file.   Or ride till it wears off :)