Hi Carlos,
At least since version of 12/02/2010 I'm getting some weird turn instructions in places where they worked fine in the past . In this area [1] I get two of these estrange instructions when driving SE from "Avenida Cordel de Merinas" to SW in "Avenida Hernán Cortés". The sequence of instructions (both MapSource and gps) is: 1-Turn right at Avenida de Extremadura (OK) 2-Turn left at Avenida de las Delicias (wrong) 3-Turn right at Avenida de las Delicias (OK) 4-Turn right at Avenida Hernán Cortés (wrong) At 2 there's been no change in the data for a long time. I noticed 4 first time after creating a through_route relation to avoid a "keep left" instruction, but the problem could have been there before. nuvi gives another wrong "turn right" at 3.5
With that patch I posted earlier, this route is fine now in mapsource (no spurious directions). Are you still seeing problems with that route? Cheers, Mark