This issue is already fixed in master branch - see line 102 of MessageCarbons plugin.

Hi

I am looking for a commit in your git related to this issue so that we can patch our server. But I could not find one, do you know which commit it is?

Thanks!

I actually I found it, there is no specific commit, just as you mentioned, it's in line 102

    if (session == null)

            return;

Thanks!