Do you have squid (and) squidGuard packages installed by chance?
If not do this:
Click "Diagnostics,>Ping,>Select the LAN interface,> try google.com
copy/paste the output of this back here,,,
You will no doubt get 100% drops but the return values may help to determine what is dying.
If you do in fact get replies on the pfSense box you know your routing is jabber wokied somewhere to the vlan…
BC