In regards to the chdir, it is also present in the 2.4 from what I read https://forum.pfsense.org/index.php?topic=124158.0, but unbound works fine.
In regards to logging restart on reboot, it's just annoying and I restart unbound on each reboot as I don't reboot often.
Another post on the same issue : https://forum.pfsense.org/index.php?topic=123554