I don't know if this started with 14.20, but I have noticed recently that my 5X is not ignoring super-outlier power spikes that my other units (Edge 520 Plus, for instance) are.
I would imagine is what is happening is the powermeter reports an outlier that is likely incorrect and the head unit properly ignores it... this is the case with my Edge units and I think the Fenix used to do it, but definitely I'm seeing crazy spikes JUST with the Fenix when I record the same activities with both types of units.