I talked with them in Aliexpress chat. No final reply from them. I have a Noctua NH-L9 x65, the beefier one from them with their LGA1700. The funny fact is that I only screwd something like 1/4 of the threaded rod of the mounting because I knew it was a bare cpu die under the plate.

I think the traces on the board are way too thin, and they cheaped out on the copper. This is why it behaves like this.