BUG (?) - oAuth refresh token in database expires in 3 months !

Good day. I discovered that the refresh_token in table bx_oauth_refresh_tokens are all set to expire in 3 months and the table is getting filled with lots of unnecessary refresh tokens.
For example a token generated on 29th May at 1:52 AM  in table is set to expire on 26th August at 11:52 PM. That means that each time the access token is used, a new refresh token is being inserted in the database. 

How can I avoid having millions of different refresh tokens in the table? For example a single user_id has 5 or even more refresh_tokens assigned to it

The cURL command i use for authenticating my users is curl -X POST "[SITEURL]m/oauth2/token?" -d "grant_type=password&username=[mail address]&password=[mypassword]&client_id=[cliendID]&scope=basic"