SOLVED
FreeBSD does not read the hardware clock correctly from the Odroid H2. This causes all sorts of weird problems.
johnsond in the Odroid forum tested the board and found a solution, all of which he described in this post: https://forum.odroid.com/viewtopic.php?t=33911#p261986
Go to System > Advanced > System Tunables.
Add New
Tunable Name: kern.timecounter.hardware
Value: ACPI-fast
Description: TSC-low doesn't work on Odroid-H2
I've testing this on two Odroid H2s. After rebooting, the boards were able to sync with NTP, the time was displayed correctly, and pfSense could contact its repository.