Missing Session Id

Every time On_connect event triggered, Session_Id created in the debug log. But some time this session Id not created and giving “null” value.
Have any idea when and why this is happening.

This does not look like expected behavior.
Will you be able to help us with the below information?
Which instance do you see this issue in? https://bots.kore.ai/botbuilder?
What is the frequency of occurrence?
Can you please share your bot export (rename JSON files to .txt extension and zip it back) with koresupport@kore.com?