I too have been dealing with this issue and have updated to IOS 7.0.3.
I too set both alerts for every event, and they constantly reverse.
I found a short term fix but I agree this is really a bug in the IOS.
Go to the default alert times in Settings.
Settings>Mail, Contacts, Calendar.
Scroll down to Default Alert Times.
I set Events to NONE
I also set All Day Events to NONE.
The problem seems to be resolvd for now, but not sure why this had to be done.