A location was logging errors that EIGRP Hold Timers expired. This was happening at random anywhere between 30 minutes to 2 hours. When this happened, it would drop reset the EIGRP neighbor and trigger their failover connection causing users to get disconnected.
The default EIGRP hello timer is 5 seconds and the hold timer is 3 times the hello timer (15 seconds). I read that for less stable connections that setting the hello and hold timers to a higher value could help. At first, I tried 20 second hello / 60 second hold timers and noticed that EIGRP was staying up longer between 2 – 6 hours. I then increased to a 30 / 90 second timer, and EIGRP has not dropped since. You must put the hello and hold time commands on both ends of the tunnel for them to take effect.