My goal is to scope and refine search results by content type and to present the content types with the object in the search results. I all of these "working" but my  custom content types are not consistently applied to my objects, instead I see that sometimes SP has substituted mimetype instead of my content type.

It appears completely random or as though there is a conflict of some kind. Some of my custom content types are applied to all of my objects correctly, some applied to no objects at all and some applied to some objects.

I have created multiple custom content types including Policy, Procedure, Process Map...etc.. I created a new managed property mycontenttype and mapped the crawled properties Basic:5(Text) and ows_ContentType(Text) in that order to itthen executed a full crawl twice. I have since backed out the Basic:5 mapping and executed a full crawl with the same results.

Using mycontenttype in the search scopes works correctly and the refiners I receive work correctly and appear in the search results themselves (after adding a fetch for mycontenttype), but I can see in the search results that not ALL of my objects have my content types... instead mimetype is in mycontenttype "sometimes" as I described above.

I am assuming a full crawl completely resets all relevant indexes?