Detected ADSB aircraft with jumpy track?

[russp]

The aircraft on the aircrew playback is jumping backwards and forwards but it's shown as ADSB which should surely be the most accurate and reliable track information? It also appears to be flarm and is not being mlat'd - so what's making it's reported position so variable? Something doesn't seem right. 
See youtube video of playback here - https://youtu.be/QzuTC5LyJOQ
Track file is here (if it helps)  https://drive.google.com/file/d/1gMvS7gNiun0QYMfs9bA_u4Mvr6rFjA43/view?usp=sharing

[Admin]

This is interesting
I do not see a ground-station based where that position is on the aircrew map.
although I think I may know what the problem could be, there was a bug in an old version of OGN-R which persisted a last known position report if it has not received an update.
As this is dual emitting (ADS-B/FLARM) the FLARM is repeating the last known position

I need to track down who owns this station, thanks for alerting us.

thx
Lee