I see what the issue was; rcecylers (and buildings in general) that are already on the platform (on the surface of the planet) are kept and warped to the next surface, and my code wasn't accounting for that; it was just clearing the list of recyclers for the new surface, so trying to remove a recycler that wasn't on the list.
I've changed a bit of the code so that (in theory) when the surface changes, the new surface is scanned and added to the list. I'm not sure how this will interact with moving between the internal surface of the warptorio.. ship thing, but it seemed like everything was working, and not crashing, so hopefully that's fine. Now I'm concerned if these changes affect space exploration in some way...
But this particular crash should be fixed as of v8.2.10
EDIT: I released a follow-up shortly after, since I left some debug code in, among other issues. Potentially fixed as of v8.2.11