The post above references this as a problem, where it is actually what I want it to do.
There is also the message the comes up when deleting a renovation filter
"By deleting a renovation filter, you will lose all elements which are shown ONLY on that specific filter and which are reserved by you. Elements not reserved by you will be visible on all relevant renovation filters. This operation is NOT UNDOABLE."
In my case, regardless of the fact that I have the elements reserved, deleting the renovation filter makes all the previously pinned elements visible on all relevant filters. Which means I end up with a bunch of copies of elements and geometry for design options that are no longer valid. Kinda a weird case where I want Archicad do delete my stuff lol.