Calendar Shared with me not synching

I have an iphone 12pro with IOS18.5 - My wife created a shared icalendar which we both use to keep track of all of our appointments and trips. It works great on my laptop however my iphone does not consistently synch. I have made several doctor's appointments that conflicted because existing appointments are not showing up on my phone. I have looked at everything but cannot find any settings to set or improve synching. My wife's iphone 16 synchs with no problem.