Calendar not fully updating
I keep one calendar on a Mac and update my iPhone Calendar using Finder and a cable connection (please, no advice to use iCloud). I have recently needed to add an entry for 9 January 2026 which has gone onto my Mac calendar. After several updates of my iPhone calendar the entry for 9 January 2026 is still not there. Scrolling through future years on the iPhone I can see that in January 2026 there are regular weekly activities scheduled but if I click on any of these, the calendar switches to June 2023 with entries for that year. It is as if it has a built-in read limit of 2 years from the current month i.e. June 2021. Is this a settings problem that I am not getting the update on my iPhone for January 2026 ?
iPhone 12 mini