No, not unless one or more has gone bad. You need to have their bias adjusted and matched.
Yes, and further to that, I strongly doubt that it is a tube fault at all. It's far more likely that some part of the bias circuit has failed. Traynor has had serious problems with stage regulation because of part failure in all their modern tube bass amps to varying degrees. I suspect that the amount of electrical heat being generated is above the thermal limits of the bias circuitry, either a connector, resistor, board joint, or any combination of the above. The potentially bad news is that if the amp ran this way for long, it may have toasted half of its output tubes already, and if you just buy new ones and stick them in there, the new ones will overdissipate too.