No Google, that is not how you convert meters into feet.

But it wasn't. I get the same result for this exact query. It seems to be like explained in another answer: Google interprets the "m" as million and the "in" as inch, so it gives you just some conversion for 17 million inches. It's a bit random here how Google interprets things. "17.21 m in" (that one really could mean 17 million inches) is correctly taken as a meter-inch conversion, while "17.21m in" does a conversion from 17.21 meters to kilometers (where are they coming from?).