Last Known Position is drifting

After re-setting the last known position back to the receivers Lat & Long four hours later it has drifted to the south east form the
original position 38.747308. -90.628011 changed to 38.2995441719323, -90.0901827650995

site identifier b8:27:eb:ac:f6:6f Site 3783 - KSUS and has changed again while I generated this post

Last known position: (38.079195815947, -89.796648923775)

Site 3826 - KBDU
Site identifier: b8:27:eb:00:c3:4c

I am having the same problem.

I reset my position to (40.03, -105.32), which seems to stick for a little while:
Last known position: (40.03, -105.32)

But then a little later:
Last known position: (39.8405015075686, -104.67235821824)

Last known position: (39.8545736680307, -104.67682981192)

Is this by design? Is FA trying to obscure my exact position for privacy purposes?

I think this is a bug as per ads-b-flight-tracking-f21/nearest-airport-and-location-off-t19443.html