I’m also encountering this problem, with a twist.  I’ve installed the plug-ins on two machines, both running Reason 10.  It shows up in one browser (iMac. late 2015, Mojave) but not on my older MacBook Pro (early 2011, Sierra) which is a shame because this is my main work machine.  I’ve also had no difficulties with products from Softube, Novation, IK multimedia or Arturia.