Hey Thomas, I may have fixed this problem by trying to sort out something else. Maybe this will help you?
First, it's worth noting that when I first set up my phone, I installed Microsoft Outlook and through that app my Outlook.com account was added to the phone. Coming from a Lumia, I'm already invested in the Microsoft ecosystem of apps for Office and mail, so I was only planning on using this for my mail, calendar, contacts, etc. I was NOT using the Samsung Email or Calendar apps, but I was using the Contacts app (which was set to be in sync with Outlook, my Comcast account, and my work account (which is Office365 based).
It's the above set up where I was adding favorite contacts to the People Edge app, and which would disappear after an hour or two.
Because Outlook doesn't sync with the Samsung Calendar app, and because you can't set the Outlook Calendar as the default, I decided to remove Outlook and try using the Samsung Email and Calendar apps for awhile, see if they were worth keeping. To do this, I removed my Outlook.com account from Settings/Accounts, removed Outlook as a phone administrator from Settings/LockScreenSecurity/OtherSettings, then uninstalled the Outlook app.
Adding my various accounts directly through the Samsung Email app (and by extension having them sync to Calendar and Contacts), I immediately noticed that my contacts were present in a more 'complete' state - all contact pictures came over, etc. That wasn't the case before. I've added five contacts to the People Edge app since that change, and as of right now (more than 12 hours) they are still there. So, I've at least gotten past the 1-2 hour mark, but I've got no idea if this is permanently fixed or if it will happen in a few days, weeks, etc.
I also can't confirm what step here actually fixed the problem:
- Maybe contacts in sync from Outlook app don't play nicely with People Edge?
- Maybe the contacts were in a bad state from when they were first added, and it has nothing to do with Outlook being on the phone?
- Maybe adding the accounts outside of Outlook makes a difference?
I'm going to live with these apps for a bit to see if I miss Outlook vs having the Calendar integration be cleaner, but either way, I figured some of the above may help you out. Good luck!