Klaas
If you are using Metric units for your telemetry I am afraid it is a confirmed bug. See my posting in the
Spektrum's Recent Airware Updates in RC Radios, Transmitters, Receivers, Servos, gyros post #18. In brief however, if you select US units for the Telemetry rather than Metric all works fine (with a small caveat that if the sensor believes it is at a negative altitude it reports it as 'number too big') . No doubt the bug will be fixed in a later firmware release.
Regards
Ian