Hi, cocacolakid

0-10 v smells driving and regulating high Power units ... could you catch high voltage spikes on the AOP output , due to the drive line ...

Note, you surely drive a long line whose capacitance is not negligible nor. Have remarked output HF oscillations ???

This makes me think an AOP with full bipolar output ( 3140 is NOT full bipolar ...) and clamping diodes to VCC and GND has to be tested here .
I don't think 10^12 ohms input impedance is compulsory not to trouble the PWM to DC filter ...

The more I will know, the more I will help ...

Alain