Tables and other metadata from a plugin appear in an instance where that plugin is not installed yet. Often the source of these records is unknown. However, if you are seeing things like an inaccessible sys_db_object record with no associated columns or data, it could be due to this common issue.
All Supported Releases
This issue occurs when a plugin is activated on a sub-prod environment, and changes to some of the plugin's records or associated data are carried into higher instances via update set.
You must not perform any development that involves or depends on records from a plugin when that plugin is not activated on all instances yet. Activate the plugin on all instances before starting development.