Ah, of course. So the idea that length contraction makes the pressure go up is at best a heuristic; it can be a good thought starter but it won't give you a correct analysis once you dig into the details.

There is no point in continuing this discussion if you are going to continue to misunderstand and misrepresent what we say.

As @Orodruin commented earlier, this topic is really not a "B" level topic; it requires at least an "I" level background to be able to go into details. The best "B" level answer that can be given is what has already been said: there is a tensor called the stress-energy tensor that represents energy, momentum, and stress; the components of this tensor do change when you change frames; but the change cannot be simply described as "pressure goes up because of length contraction"; it's more complicated than that, and the complications require an "I" level discussion.