I saw this comment because I always like to check for possible problems for diving in headfirst..
Types (part of the TVC Toolset) is a plugin which allows one to create custom post types, and when used in tandem with the Views sister plugin, allows one to create very complex custom queries and display them just about anywhere.
I can see why trying to switch custom post types that are rolled into nested custom queries might cause an issue, and suspect one would need to bring the post type being switched into, under the control of Views (if it is not already).
But then it is unsurprising that any relationship breaks while switching, because the relationship is created within the TVC rule-set, which operates outside of the “normal” WP options (at least when the relationships are in process of being created).
I can confirm that I have used a much older version of the post type switcher to successfully switch posts between cpt’s created with Types, but have never tried to switch types that are hooked into complex relationships (or while being displayed as custom queries via Views).
I don’t know enough about how the many-to-many relationships work in complex custom queries, just enough to imagine this might be rather tricky to solve.
These are the ones in question:
https://wp-types.com/home/views-create-elegant-displays-for-your-content/
https://wp-types.com/home/types-manage-post-types-taxonomy-and-custom-fields/
