Nah, a hard reboot of the XB1 made it go to 100% - I did a quick Google search about frozen at 99% downloads on the XB1, that is the fix! Just turn it off and on again!
Just like any tech...haha But not off and on again from the controller - you hold down the X button on the console for 10 seconds as a hard reboot!
After that it was 100% then the other games downloaded fine. Probably an issue with the CoD4 remastered game being 63GB total and my 1970s copper phone wire that my internet goes through at home SUCKS!