Why is Teams opening instead of webex?!

So I’ve been sending outlook calendar invites for webex meetings via email… very normal. Usually it’s fine but every now and then there is an option to ‘join’ meeting in the calendar invite. But this then opens up a Teams meeting. I don’t ever add a Teams meeting to the email invite. I only add Webex meetings. But then in outlook calendar it has a button to ‘join’ and that then opens the meeting in Teams. It’s so frustrating because then we waste time having to get people to move across to the Webex meeting they’re supposed to be in, not Teams. Can anyone tell me why this happens and how to fix it? Thanks!!