Henry's, one of the compounding pharmacies, says that they get the chemicals from legitimate licensed producers of feedstock [1].
There is a compounding loophole, but there is no loophole for patent encumbrances -- if a compounding pharmacy is violating NN's intellectual property, then can just sue them directly; they don't have to pursue the regulatory crackdown they're going for now.
There are companies that do grey/black market reconstitutions, like Pivotal Peptides. But they are not compounders. The compounders are legally selling the real thing directly to customers. Do you have a specific source that indicates that any compounding pharmacy is getting its feedstock illegally from China?
[1] https://www.reddit.com/r/henrymeds/comments/1av14cm/comment/..., discovered via https://www.astralcodexten.com/p/the-compounding-loophole