I had a bad capsule on my LSD2 (Studio projects replaced them both for free) where dampness caused it to arc-out. It sounded like "pop and then slowly recover", and they look differently from what you have. I saw a huge instantaneous excursion, and a decay curve as if goes back to normal over a second or two. That's not what you have here.
Any other attributable cause? Cable connection that's looking flakey? Anything that might contribute to dampness issues? In Maine in the winter time for instance, you have to avoid having mics get cold in the car, then when then hit the warm air in the bar they will "fog up" like a pair of eyeglasses.