Can you check your content template renderer repository for particular content type? It's pretty easy accessible via EPiServer Developer Tools plugin.
You probably need to specify clearer what controller to pick by either using a more specific contenttype in the controller definition than the one you are using or marking one as default controller. If you have multiple controllers for the same basetype Episerver will have a problem resolving which one to use...
In the process of upgrading site to latest version [9.10.2] from 9.6.1 and it happens for certain page types episerver is resolving the wrong controller. It correctly resolve content type but then picks up the wrong controller and thus throw type-mismatch error in model binder.
Both controller refers to same base contentType and then action index has actual contentType.
Before I start going deep down in our code base can episerver tech team help to find out if there is any change in the way episerver handles routing in 9.10.2?
Having said that same code base works perfectly for 9.6.1 , it looks like may be a bug or un-documented breaking change in 9.10.2?