thanks for the reply and the logs. The log timings are similar to what I would have expected (but didn't get) from mine.
As you say crew error is unlikely - also I noticed more than those 2 examples over the last day or so.
I might email Radarbox suport and ask them to investigate. Has anyone else noticed this in their own logs?
OK, I've been doing a bit more investigation.
Out of just over 1000 flights logged so far today in MyFlights, 152 show a duration in MyLog (StartTime to EndTime) of over 90 minutes.
Since most of what I pick is either arrivals/departures from the London area airports or high-level overflights, clearly that's nonsense. Apart from the odd loitering ASTOR or Islander, or VFR flight pottering about locally, nothing is going to remain within range of my RadarBox for an hour and a half.
Closer examination of the log reveals the same problem you have experienced - arriving flights, instead of timing out when the aircraft drops out of coverage, are being artificially extended (sometimes by several hours) until the same aircraft departs on a subsequent flight.
For example I have BAW565, inbound to Heathrow from Milan, on my SBS-1 for 20 minutes (12:01-12:21 local), but in MyLog in RadarBox BAW565 is showing as having been tracked for 147 minutes, from 12:15 to 14:02 (i.e. until after the same aircraft's subsequent departure as BAW908N to Frankfurt).
Same with overflights - RadarBox shows RYR4KA (Hahn-Dublin) tracking OTT at FL400 for the best part of
3 hours (07:28-11:09), by which time the aircraft in question was well on its way back to Germany again after a turnround at DUB.
Looks like one more entry for the bug-list, I fear ...