This box originally started with pfsense 2.2, but has since been upgraded to 2.3.1 (Patch 5) along the way.
Perhaps something was strange during the update or upgrade process or plain was going wrong
pending on one or more packets that where installed on your pfSense box.
I would try to install version 2.2.6 clean(without any packets), fresh and full (mSATA, HDD/SSD)
and see if there will be a problem or not if all is fine running and working well it could not based on that version
Then after trying out that I would try out then to install the latest version 2.3.1.5 but also clean(without
any packets), fresh and full (mSATA, HDD/SSD)and if there will be any kind of problems then you would
be clear to say from where it comes
And then you might be sure to say with which version you might be going along the next time until
it will be updated and/or a newer version will be there, so you can test this from time to time until
you will be seeing any changes in the support, stability or other things.