Different distance values for same device & time range between Traccar 4.10 and 6.5 (FMC150)

We are observing different distance values for the same device and same time range when generating trip reports from two different Traccar versions (4.10 and 6.5).

This issue is consistently reproducible for one FMC150-series device, while another device of the same model works as expected, which makes the behavior confusing.

6.5 Output

{
  "deviceId": 62732,
  "distance": 64896.0,
  "averageSpeed": 14.52,
  "startTime": "2026-01-02T23:47:30.000+00:00",
  "endTime": "2026-01-03T02:12:13.000+00:00",
  "startOdometer": 3.5729044E7,
  "endOdometer": 3.579394E7
}

4.10

{
  "deviceId": 62680,
  "distance": 65295.0,
  "averageSpeed": 22.81,
  "startTime": "2026-01-02T23:47:30.000+0000",
  "endTime": "2026-01-03T02:12:13.000+0000",
  "startOdometer": 1.205392565E9,
  "endOdometer": 1.20545786E9
}

Difference: 400 meters for the same trip
Odometer scale is completely different

Could you please help us to figure out whats the root cause for this mismatch ?

It could be related to fast reports. How long is the time period you're using?