EEVblog #490 - Peak Detector Circuit - Queries

[2X]

Hi guys,
I saw many times the video "EEVblog #490 - Peak Detector Circuit" where Dave explains the "Peak Detector Circuit" and I can't understand two things. First of all why the capacitor's output (blue waveform) follows the input  voltage (yellow waveform) while the operational amplifier's output is negative (Picture 1)? Second this reverse peak (picture 2) is due to the parasitic capacitance of the diode? Thanks!

https://youtu.be/jllsqRWhjGM?t=1574

https://youtu.be/jllsqRWhjGM?t=1556

[rs20]

1. Could be parasitic capacitance in the diode,
2. Could be either parasitic capacitance in the diode, or the diode could be experiencing a long turn-off time, or both.