Graph shows draw in theoretical win, even though evaluation is #-20

Here in move 47, the analysis is #-20 (above the moves panel) but in the graph the line is flat. Is this a bug? I believe this is a theoretical draw.

I think this is indeed some kind of bug, but in the sense that this is lost for white! Looking in the analysis board and the corresponding tablebase for the position you mention, it is clearly loosing.
You are right that for some reason the graph line is showing an incorrect evaluation.

@SoothingDisturbance - weird...

I've got no words to explain this...

I checked and in the variation after kh2, it shows g5, not Kf3. Is this another bug?