Repeating events in the default calendar app is currently bugged out from all sides. In my case, they’ll show a day early, and show events that flat out don’t exist, but per the repeating calendar rule should (Example, Monthly event on the 3rd Tuesday of the month, except July - July is deleted manually from the cycle)

It appears to me that they’ve decided to read the initial repeating event, and use that data to populate the others, right or wrong.