If you’re using the nvidiaexp PPA, and the driver installs/builds properly, there’s not much I can do to fix bugs since most of it is closed source.
Again, you may have bought it “new”, but that doesn’t mean Nvidia/TSMC has made these cards recently. It could have been sitting in a warehouse for 8 years. You bought a GPU that was first released over 10 years ago and Nvidia stopped officially supporting the 390 driver (and so, Fermi core cards) on Linux over a year ago. Complaining will not change that.
Either return the card(s), use the open source nouveau driver, or hope you can solve the bug with 390.
Good luck.