Look through the solutions offered earlier in this thread.  Instead of printing the Invoice, download it to Adobe Reader, print it and save it from there.  You may need to just spend the time and figure out some variation of that short-term fix like I did.  It is a pain and takes additional steps, but can work...short-term.

There is NO URGENCY shown on the part of Intuit / QBO to address this issue and to make QBO work with MacOS.  They only argue that it is not a problem on their end while Mac apparently does the same.  Silly me, I thought that software needs to be written in a way that it operates on a given operating system.  

Actively looking for other providers that may care a bit more about their subscribers!