maybe a capx is needed, but from the top of my head:
every obstacle you want needs to A) have the solid behavior, or B) be manually added to the custom obstacles for the object with path finding. (in any case select the proper obstacle type in the behavior properties)
Also, obstacles are not updated unless you "regenerate obstacle map".
To avoid over saturation, I recommend regenerating the obstacle map only when needed. Like in the same event that finds the path, though you need to make sure the "regenerate obstacle map" action is above the "find path" action.
Hopefully is a simple problem like this ^^