Hello Alex,
This is due to a known issue where the def:CommentOID is being duplicated in the WhereClauseDef. Only corresponding ItemDef should have def:CommentOID.
Our team is currently working on a fix for this issue which should be resolved in a future release of Community. Until then, the only workaround is to manually remove the def:CommentOID located with the WhereClauseDef.
Kind regards,
Matt