While trying to look up an existing issue by its identifier, I discovered what appears to be a bug in the Plane connector/API integration.
The connector exposes an archive field for the archive action (used to archive/unarchive an issue). However, this same archive field is also being sent automatically with other actions that do not support it, such as:
list
retrieve_by_identifier
search
count
As a result, the server rejects these requests because they contain an unsupported parameter.