level_head found this one: Balmorhea, TX to Houston, TX
There's an apparent discontinuity in the path it wants you to take. Additionally, if you look close up, the line on the map from the 10 to the 410 is a bit off.
Best guess? The 10 seems to turn into the 35 and then swap off to the 10 again. It looks like that's a discontinuity according to Google nad it messed up famously in trying to backtrack a route the other way round.
Naturally, the reverse path works fine.
A general view:
A close up of the discontinuity: