Is this a blown tube? (pics inside)

[Elpelotero]

I was looking at my rectifier tubes today --mesa 5u4gb-- and noticed one of them is "burnt" on the bottom. almost like a lightbulb when it goes out. i still have the warranty, so can i get a new tube? it was like this as far back as i can remember, but brought it up now.

the bad tube there

versus the good one here

 

[Bobbypols]

get a new one. call them up, i got new tubes from a burnt el34.