Of course nobody wants a defective unit, but assuming it's a worldwide problem because we know of 3 or 4? I don't know how many have problems, but I do know Yamaha is quick to replace them. Until they can discern if and where a problem exists, that's all we can expect. To ask for a total recall because of a handful of problems seems a little radical to me.
Korg sold me a keyboard that was virtually unusable because it sounded like it had a blanket over it. Nobody clamored for a recall, but evidently they did address it at least somewhat with an OS update.
I think it was several OS updates before Roland's G70 became acceptable also.
We don't know if these problems are hardware or software related, or even how many are affected. I know mine was damaged by UPS, as is ALMOST EVERY PACKAGE I GET FROM THEM.
I wish we could recall UPS, at least in my area of the world.
I gotta go make a living now!
DonM