The calls to `to_geometry_set` in this file can create a temporary
Instances struct for collections. That instances component will contain
two attributes, which are currently referenced in the attributes map
even after the temporary compoment storage goes out of scope. A simple
fix is to avoid adding these attributes to the map in the first place.
An alternative that would also be more efficient would be to handle each
instance reference type explicitly, without converting it to a temporary
geometry set. That seems to significantly complicate the code though;
for now it doesn't seem worth it.
Pull Request: https://projects.blender.org/blender/blender/pulls/140999
8ebb759046