Recorded speed varies wildly and energy usage way too high

Since the last few weeks it seems that ABRP is recording some strange speed reading during my daily trips. In turn it seems that this is influencing the energy usage predictions, which were spot on before, but are now often more than 10% off.

When looking at the recording of one of my daily trips, I see that the speed on the highway fluctuates wildly between the 100km/h I was actually driving and around 50km/h. Also the reported usage for the trip is shown as 1042 Wh/km.

Other trips show more realistic energy usages in the 150-180 Wh/km range, but still show the jittery speed graph. There are also a few trips that simply report 0 Wh/km which also seems suspicious.

The issues with the speed seem to have started on March 14. Earlier trips show a much more consistent speed on the highway.