facing Invalid Refresh Token Issue


We are accessing sugarcrm application from multiple environment using one demo instance with same client id and client secret.

The scenario is with one demo instance and same client credentials

1. On first environment , if we test connection ,will get access token a1 and refresh token r1

 On Second environment with same demo instance and same credentials if i tried to execute test connection parallely,i will receive new access token  a2 as well as new refresh token r2 

first environment received  access token a1and refresh token r1 will become invalid. 

Is this expected behaviour from sugarcrm application end. Can you please confirm?