Session count metrics issue

[gopitcsce]

Hi All,
Recently I had integrated dialogflow bot with chatbase. I am passing both userid and sessionid to chatbase api , both are different values. I could see that the session count metric is not correct in chatbase in the below case,

When a single user(same userid) is having multiple sessions within 15 minutes, only one session is getting counted in session metric dashboard, eventhough the sessionid's are different.

Can someone please help on this issue??