No help, sorry, but this has just happened to me with both ides, & also now, my right decks tempo slide is unresponsive & the virtual decks start slowing down BPM even though I'm not touching anything. I tested my controller on another laptop & the issue was still there, which indicated a firmware issue.
I opened a support ticket on the serato website & they suggested I take my controller to a local service centre (they are all OS), so I'm taking it back to the retailer I bought it from to get it fixed or replaced.