Halo Wars 2 Installation slowed to a crawl?

I’m installing Halo Wars 2 Ultimate Edition, and the first 40% installed in about two hours, and the next 16% took nearly three hours.
I’ve got another 10.5GB to go, but it says its ranging from 400KB/s to 2GB/s, so it’s looking like it’s going to take a couple entire days to finish installing (and that’s not even including the code for the Season Pass or Halo wars Definitive Edition).

Are there any explanations for why it slowed down so much? Any suggestions for what I could do to speed it up?

Update: in the last hour it ticked over one percent, so it is now at 57%.
I’m installing it on my XB1 off of a disk, and I’m only using 23.7% of the memory on the XB1, so there’s no reason I can think of for the download not progressing like it should.

edit:
Update 2: the install speed seemed to pick up a little, and it looks like it should be finished installing by sunrise… hopefuly. Then I can start downloading the season pass and Definitive Edition. Maybe tomorrow evening I’ll be able to play.