iPhone calendar app widget selecting shared calendars to display on its own

In the iphone calendar app Home widget, when i click on an event, if that event is also on the calendar of someone who has shared their calendar with me, when i leave that event their calendar will be automatically selected to be displayed from the calendar list. I couldn’t find a setting to control this so it seems like a bug. Is there a fix?

For reference all shared calendars are hosted on the same Microsoft outlook/exchange (SaaS) work tenant.