Outstanding queries after upgrade to 4.4.5

Any update on the “right way” to handle these table references?

And FYI, I have similar problem on a 4.4.13.
I checked that the
client_id in oauth2_user_client_xref matched
the id in oauth2_clients.

And they are of the same type and length.

DESCRIBE oauth2_clients;
±--------------------±-----------------±-----±----±--------±---------------+
| Field | Type | Null | Key | Default | Extra |
±--------------------±-----------------±-----±----±--------±---------------+
| id | int(10) unsigned | NO | PRI | NULL | auto_increment |

DESCRIBE oauth2_user_client_xref;
±----------±-----------------±-----±----±--------±------+
| Field | Type | Null | Key | Default | Extra |
±----------±-----------------±-----±----±--------±------+
| client_id | int(10) unsigned | NO | PRI | NULL | |