Well it was Stone, and the ranks here were questioning its nobility a few months ago. I had a good batch of Stone right before the questionable batch came out, but this batch was a gift bought for me a few months ago that I just opened. If I have a little it's fine. It's when I have 4 or more heaping tablespoons, I feel fuzzy the next day. Normal kava doesn't do that to me.
VanuWAKA is like that for me. 3 TBS is fine but 4 TBS is way too strong for me. But I don't think that's because it is tudei, I just think it is SAF (strong as fiercelycouldbe) kava.
Over on Amazon product reviews I've seen tons of reviews where people claim a perfectly noble kava is tudei because they didn't prepare it right and felt bad. To a certain extent "tudei" doesn't even mean tudei any more, it means in popular usage "I had one bad experience that might have involved user error but I'll slag the root, and tudei for that matter, because, well, it can't possibly be me, right?" Poor vendors are trapped in the "customer is always right even when he isn't" situation, and even more tragic, lots of perfectly good root gets destroyed.
Best practice is always go light on any new strain, vendor, kava, prep or even batch until you know for sure.