Opamp output unexpected ripple
You can't drive a cap directly in this way.
Add a small resistor of e.g. 33 Ohm in series after U7C
If you don't have space/footprint to do this, then replace the cap with a cap+resistor series combination.
Also you mentioned, that already the first opamp is noisy. I see you decoupled +15V to -15V.. this is not much use if your output is GND referenced. Each supply should be decoupled to GND.
It can be though that the cap makes the left opamp oscillate and this affects the right opamp as you don't have decoupling caps.