It's weird, for some simulations if I want to use a minimum of 1000 points or more, I get a 4 Vp-p ~10 MHz oscillation... As soon as I lower it to around 500 - 1000 points it's fine, but I can't tell whether the signals are getting clipped due to the circuit, or that there aren't enough points to represent the peaks.
For now I did some testing with keeping Rf = 10k on U5A and playing around with the working and counter electrode resistances. I made a mistake with my ranges beforehand, those resistances can be between 10k and 100k in reality. So what I noticed is that if Rwork is larger than Rcount, the reference voltage signal (-Vbias) comes out nicely (not clipped), but when Rcount > Rwork, the signal is majorly clipped and distorted.
Again, because of this weird oscillation I can't fully tell whether the signals are behaving normally because I am limited to 500 - 1000 points.
Any thoughts?