Halo Wars 2 has received a major patch update on Xbox One and it is a whopping 9.9 GB fixing major issues such as gameplay, crashes, performances, audio problems and some known issues. 343 has stated that they are working to get the Windows 10 patch out as soon as possible and the current ETA is ideally within the next 24-48 hours.
They explain why the Xbox One update comes out before the Windows 10 update:

While we regret that PC players have to wait a bit longer, the team didn’t want to delay Xbox One solely on account of the Windows 10 release. Due to the much more complex nature of the PC platform everything just takes a little bit longer (certification pass, testing, etc…). We will provide updates as new information becomes available.

Here are the gameplay fixes:

• Fixed issue with ‘Detect’ on some starting units not working properly
• Fixed an issue with getting the Palmer’s Pure Gold Achievement
• Fixed some bugs with Kodiaks in Campaign
• Fixed a bug with garrisoned Snipers not getting additional stats
• Fixed issue with squads getting stuck trying to garrison if another squad beats them to it
• Gold medal can now be more easily attained in ‘Hold the Line’
• Fixed a Cyclops and Reaver pathing bug where they would sometimes stop moving
• Fixed an issue with units getting stuck in bases after being made
• Fixed various skull functionality not working on some units or abilities
• Fixed some cross-skull interactions between Annihilation and Pestilence
• Fixed some Locust pathing issues in Blitz (even though they’re driven by Grunts)
• Fixed an issue with units becoming unresponsive in Blitz
• Fixed an issue in Blitz with units getting a x4 speed boost in a specific situation
• Fixed a conflict created by swapping d-pad functionality in Blitz
• Fixed an issue with the Blisterback not recovering from damage in Blitz
• Fixed behavior of Marines sometimes failing to get new targets after throwing a grenade
• Friendly cloaked units now appear on the minimap
• Made some adjustments to Scarab creation
• Tweaks to Grunt Mob, Bloodfuel Grunts, and Bloodfuel Locust
• Holo Decoy can no longer be used on Pelicans or Spirits
• Fixed card level of units affected by Holo Decoy not showing over clones
• Glassing beam always creates vision now in Blitz
• Adjusted AI to make better use of Healing and Cloaking fields
• Skirmish AI now uses Extraction and Teleport
• AIs have been practicing their Domination game

You can read the whole page on Halo Waypoint here
We gave Halo Wars 2 a score of 9/10.