@joelhaggar Thank you for the information. I was able to look through the NTP and timesyncd config files, and things looked alright. However I discovered I was having problems with internet connectivity and DNS resolving on the device in question. I discovered that it didn't have a default IP routing path. Considering we didn't need an outwards internet connection for our projects, makes sense that I didn't pick up on it.
I looked at another MangoES device on the same network and discovered it had an internet connection, so my issue was isolated. I added a default IP route using "sudo ip route add default via XX.XX.XX.XX dev eth0", and borrowed the gateway info from a functioning device. I then overwrote the DNS resolve file found at "/etc/resolv.conf" with "nameserver 8.8.8.8".
Not sure how things go out of hand in the first place, but I used "sudo date +%T -s "hh:mm:ss" to bring the unsynced time within a few seconds of the local time. I then forced the NTP to restart using "sudo service ntp restart", checked the ntp status using "sudo service ntp status", and then it looked like my ntp hosts were being resolved correctly and the time had resynced.
Appreciate the help Joel!