Probably well worthwhile to update to 2.2.5.
In your case there may be a small "risk" in that you don't really know what "fixed" your issue, but the stability of 2.2.5 over older releases is worth it in my mind.
OK I found the answer to b) is this ICMP traffic normal ? - Yes - its the default for monitoring and can be tweaked in the System / Routing / Edit Gateway section - and it works perfectly.
@Mjennings:
I have "Register DHCP leases in the DNS Resolver" checked - why uncheck this? It's the entire reason I am using pfsense as my DNS server
Because Unbound is retarded. Check Redmine and/or this: https://forum.pfsense.org/index.php?topic=89589.0
That is for pfSense itself. It is used e.g. when pfSense check for updates or for DNS lookups.
You should leave this at WAN address, otherwise the backup gets no response, cause the CARP is used by master.
Depending on his bandwidth, if he has traffic shaping enabled, the 50 packet queue depth is too small and hurts bandwidth. Making a lot of guesses here with not many facts to work with.
Could be a bit of a head scratcher, I'd look for a likely 104(?) pin IC not too far from the battery either on the top or bottom of the board.
Google is your friend if you can read the IC markings
You might get a little more info with the DMI-Decode package to give you a view from the OS POV.
And perhaps check to make sure the ClearCMOS jumper isn't on (or the pins shorted) ;)
