Unlikely that this is the issue, but try reseating all the op amps. It's an easy check so why not do it.
If that didn't fix it, check the resistors in the image provided.
If those check out, probe the gate of Q200 with an oscilloscope and see if the triangle wave oscillation error happens there, or if the function of that is flawless.
If the error does appear at the gate of Q200, check U175, U170, and U140. U140 and U175 are the negative and positive current sources for the oscillator.
If those check fine, check Q140, and Q175., though at this point I feel like nothing else can really be checked.
As a last ditch check, check the timing caps in the provided image.
If none of these solve the problem, then I really, don't have much of an idea.