This is not a bug, but I was requested to post this as an issue.

There was a feature request submitted in late 2024 to request the ability to set a cover poster for the collection that Maintainerr generates.

This was recently listed as closed by v3.8.0. However, the functionality for this has not been implemented yet. The current overlay implementation only allows setting overlays on individual items contained within the collection, not the collection itself.

Posting this here so this highly upvoted feature request doesn't get lost being listed as closed.