Why the constant updates for HW2?

Quick question to anyone who can answer this.
Why does Halo Wars 2 seem to constantly update? And by update I mean re-download the entire game.
It’s currently downloading a 43.58GB update.
At the end of last month it downloaded a 43.10GB update.
These “updates” are the size of the entire game.
What is going on with this game that it has to download the whole thing, seemingly on a monthly basis.

I believe that’s a bug with the download, I can’t remember the fix though.

My copy was installed from disc.
It’s getting annoying having this 40+GB “update” so often.

The updates have been at most 2GB as of recently. This sounds like your installation corrupted (either naturally, by forcing a quit during update, or stopping and restarting the download) and it had to reinstall the entire game.

My copy has been installed from disc since about 2 weeks after the game was released.
It had no issue installing at the time, but I do see notifications around these updates saying update failed or stopped.
Considering I use instant-on on my Xbox One, I don’t really have a choice of when the update downloads and therefore if it downloads at night when the console isn’t in use, I’m not sure how it would be interrupted.
Instead I’m greeted with 40GB+ downloads on a regular basis.