Sometime meeting invitation contains additional words in body. Sometimes it doesn't contaims... Why?

Hi,<o:p></o:p>

I create appointment in my application, save it  and send meeting invitation. I have 2 accounts on Office365 for tests: User1 and User2.<o:p></o:p>

I send invitation by my application from User2.
I receive:

I send invitation by my application from User1.
I receive:

Why is it happend? I use the same code and I compare User1 and User2 settings - they are really the same!
If I create and send invitations by Web browser from User1/User2 I receive the same resalt (as on the second picture). 

I don't need section "When: Wendsday, February 26...." b/c time in this message in UTC. It confuses clients.
How can I send invitations without additional info?

Thanks.<o:p></o:p>