I complained here about my Festivo being stuffy maybe a few months ago. A few people kind of piled on and suggested I was just a silly trombone player, and that the compensating range is always stuffy, so stop crying about it.
Well, it turned out that there was a leak in the compensating circuit on the second valve. So second line B was squirrelly and unplayable, along with any other note that used the 4+2 combination.
So Wessex paid to have it fixed at my local shop, and the local shop did a great job. I don't know how they fixed it, because the leak was in a place where you couldn't even see it, but it plays like it should now.
Just because someone is a silly trombone player doesn't mean they don't recognize when a horn isn't playing up to snuff. It took me a year and a half to figure that out, and I had to fill it with water, spray soapy water, and stuff a rag up the pipe to isolate the leak, but I finally found it, and Wessex did honor their warrantee. And now I have my very ergonomic euph back again. Just thought I'd share a happy ending to this story.