I took a look at my stats, and went looking for the missing 0.54 miles of I-526, so I clicked on the route.
The system displayed I-526, I-526BS, and FutI-26 all on the map viewer (which is fine), but connected the ends of the routes with each other. So there's an extraneous segment from the west end of I-526 to the south end of I-526BS, and another one from the north end of I-526BS to the west end of FutI-526.
Incidentally, that only happens when the username (u=ntallyn) is not specified in the URL. Once I added that, I saw the map that I expected.