I have no trouble synching my calendar between my phone and my computer, Oak. Once or twice I thought there was an issue, but it was just a little time lag or the fact that in my haste, I had put AM instead of PM on my phone and duh, I couldn't find it on my computer.
I upgraded my OS to the new one; like Oak's DH, I have a Garmin and I don't use that function on my phone.