Well, I’m sad to say that my issue has not been resolved, even after 7 months. Not only the rotary encoder did not work on arrival (it was a new S2400), but also the filter knob for the first channel was crooked and it does not rotate freely - when I turn the inner knob, it drags the outer knob and viceversa.
I did get in touch with Isla back in February. They said they were going to send replacement parts, but they never arrived. I contacted them again in May and they said they were going to look for a solution, but never answered back. I haven’t been using my S2400 in the past few months, but I no longer know if I’ll ever have a fully-functioning unit. I currently don’t have the resources to send it back.