I keep typoing 'collections' as 'collection'. Could there be any unexpected behaviour if I use
include_in_collections:collection? (A temporary measure while I'm getting all these collections sorted out.

)
Additionally: How do ignore case-sensitivity in replace_metadatas to avoid (collection|Collection|COLLECTION)? I've done it before but I can't remember.
EDIT:
(?i) (for insensitive) at the beginning of the string ignores casing.