Calendar events syncing from other calendars

My company uses a company Gmail and G Suite platform. We all “share” our calendars with each other so we can have view access. These extra calendars used to not appear on my Calendar app on iPhone. Now, however, every invitation that my colleagues receive, I receive to my phone, even if my email is not included on the invitation. I also have the ability to accept or deny a calendar invitation on their calendar. Is this an iPhone issue? A calendar app issue? Or a Gmail issue? My colleagues calendars “appear” in the list of calendars in my Calendar app, but they are all un-checked.