.dgn file association issue in Windows 10 Po?

So far (2) of my users in Win10Pro boxes can't associate .dgn files with Microstation.  There are other users with same file version/OS who do not have this issue.  File association is user-specific, so if i logon as Admin and double-click a .dgn MStation launches with no other steps required.  It is unknown as to whether additional non-Microsoft file types are an issue, but adobe and BlueBeam Revue can be set to open PDF's with no problem, and AutoDesk products are working normally.

When they double-click on a .dgn they need to select the program to open it, every time.  This is not an emergency issue, but we're pushing more Win10 boxes into the environment and I expect more complaints. 

I have been unsuccessful in finding a resolution at Microsoft's TechNet site, and my GoogleFu is obviously lacking... 

Details: 
MicroStation V8i (SELECTseries 4) 08.11.09.832

OS: Windows 10 Pro (64 bit)
       Build: 10.0.17134.345
       Version: 1803