respons on meeting request do not always show up in calendar

[Sofie]

the responses I get to meeting requests - being it 'accepted'
tentative' or 'declined' - do not always show up when I check the
number of attendees to meetings, events...
It's very difficult to keep track on attendendees when big meetings are
planned.

Can someone tell me why they don't show up and how to fix this?

Thanks,

Sofie