Old versions of the module would save records for every entity even if they matched the default settings; this was fixed quite some time ago by Dave, but sites that are running old versions can have hundreds or thousands of unnecessary records.

Comments

Title:Purge records from old releases that match default settingsPurge records from {metatag} that match default settings (legacy data)

Clarified the title.

I don't think scanning through this on update is really worth it for us, it will be costly and data intensive. The data is already there, if the user wants to fix it, they can edit the nodes.