Sync problems Mac - iPhone: Dates for whole day events don't correspond

Problem with synchronising iCal between a MacBook Pro and iPhone 14. The events covering all day which were entered on the Mac (e.g. 2-3 Oct) show up one day early in iPhone Calendar now for the dates 1-3 Oct. Starting thus one day earlier but finishing correctly on the right day.

If the all day events are entered into the iPhone Calendar first, they show up correctly in the MacBook Pro, once synchronised.

I tried disabling the automatic time zone correction etc. but to no avail.

Am using Sonoma 14.1.1. on the Mac and iOS 17.6.1 on iPhone 14 Pro

Is there any other solution to sort this discrepancy out?

TW