Wrong turns north of Alhandra?

[minha_alverca]

I’m not currently walking but I am staying close to the Portuguese central route. Twice in the last week I’ve seen pilgrims walking on the N10 highway north of Alhandra rather than taking the marked route to the boardwalk/walking path next to the river. I’m wondering if perhaps the arrows are being missed at the Alhandra turn? I was in a car so I wasn’t able to stop and ask or offer help if people were lost. Just curious mostly, but also concerned that people are taking a less safe route (traffic wise) and missing the views of the river.