Grade 2 is genuinely the judgement zone, which is why you will hear different answers from different vets about the same knee. The balance tips toward surgery when the dog is young, the skipping is frequent or worsening, or lameness lasts after episodes; it tips toward structured monitoring when episodes are rare and brief, the dog is older, and the grade has been stable for years.
What monitoring actually means: lean body weight, a note or video whenever the skip appears, and a proper recheck of the grade at least yearly. What it does not mean is ignoring it until the knee becomes grade 3, because higher grades are bigger surgeries with lower ceilings, and chronically luxating kneecaps are linked to later cruciate ruptures.
Your observations are real data here: a week of notes on how often the kneecap pops beats a single consult room examination. Bring them to whichever opinion you get, including ours.
Send the case to the surgeon. A written independent opinion, from $250.
Ask the surgeon. A written independent opinion, from $250.