(a) ground positions are not usually considered part of a flight so they don’t appear on flight tracklogs
(b) the surface position display is in beta and in some areas all data is being dropped from the coverage map.
so there’s not really much point in looking at this data until at least (b) is fixed.
Looks like you have a network problem to your FlightFeeder; the wifi is flapping. That may be contributing to the problem as if there’s no connection from the FF to FlightAware’s servers, then data received while the connection is down is lost.
To reiterate what I said above, there’s no selection of one receiver over another; positions are selected based on what data actually arrives, not which receiver it arrives from.