Formally according to GPL they are obliged to share source code only to those who get their binaries. So no, there is no any violation as soon as they provide source code to their customers.

Thing is that they can't prohibit their customers to share that source code and many will do.

But it is not clear why anybody will want to use that source code. RH is known in opensource as a company that push very questionable solutions into Linux OS making it more complicated and less transparent for users. RH is a source of multiple scandals and discord in community, and really lost its aura of one of the leading Linux distribution long ago. For independent user other distributions are much better, and only enterprise business is interested in RH, mostly because of all that bureacracy like support contracts, shifting responsibility, promises of updates and so on.

There are enough Linux distributions around to not care about RH at all.