in settings, when moca is active under networking you can see the moca xfer rates and error rates, they could clue you in as to if your signaling isnt good.
Poe filter helps in a few different ways... keeps any outside interference in the moca range out/attenuated, shrinks the "size" of the network that the tivos will try to drive the signal over and of course also improves security by keeping your signal in.
One freeze isnt enough data to blame the moca connection, it could have been any kind of glitch. Im using moca for both a mini and an XL4 and its rock solid.
-Roamio Pro/Slide Pro
-Stream (Gotta go unplug the sucker one of these days!)