My noise cancelling started to go flaky until I stumbled upon that - after I've dried it off after every use and stopped using the "case" /store pads separately from headphone things improved a lot again.
It feels like a serious design issue, I'm really confused why so few people talk about it, but I guess it's because most are just casual users of the headphones with people only wearing it a few minutes a day... And the water only really build up when you're wearing it several hours without taking it off