For none of those two files the Training Analysis Plugin shows an avg. power of 0W.
And the negative projections for power at low heart rates are "correct".
Your avg. heart rate is as high as 180 bpm and the correlation hr <-> power is very poor:
R² = 0.005.
Why? Using the GPS2PowerTrack plugin to calculate power for RUNNING with whatever parameter set will not provide reliable power values.
I don't think that runners usually train "power based". Bikers can do.
So don't believe in numbers, unless you understand what they express

Cheers,
OMB