Hi William - thanks for flagging these up. Looking at the first one (Lourdes to Perpignan) it looks as though the unusually high gradient near the 46km point is caused by a sudden step up in the elevation readings near that point when there probably should be a incline on the 1km stretch before this instead of a flat section. Unfortunatley there isn't a perfect data source for global elevation data, or at least not one that we can use as part of a free service like this, and there will therefore always be very occasional anomalies like this. However, these are normally remedied by increasing the elevation sampling interval in the route profile tool, which has the effect of smoothing out artificial spikes.
20% gradient on Ave de Quimper at approx 48.194652N 4.096955E as route 105549 also appears anomalous as road at this point follows level of canal towpath. Certainly I didn't experience anything as steep as this. I was on a single speed and would have struggled with an ascent of this magnitude
System calculates gradient of 82.5% on route de Tourmalet at approx 42.905473N 0.120345W - see route 114276