After the patch was the first time I noticed it saying "loading shaders" at all so the loading may be heavier post patch, but I only saw that message for a few seconds so something is clearly screwy for you.
So what could be the cause? You seem to have problem either writing to the disk or reading from it, but only to a certain extent. Any kind of security software could possibly cause this, and while it worked well before, the software could react differently to the patched game. Using clean boot should've worked in this case though, unless it's Windows Defender itself that's problematic.
You could try deleting shader files in case you have "temp" files that aren't cleaned up/updated properly. These are often calculated/created when you run a game for the first time or change settings, and so not necessarily part of the files that Origin checks. Though if you delete anything you should of course repair the game afterwards to make sure you have everything you need.
Another way that may clean up the shaders is if you drastically lower the graphics, restart the game and load a save, and then change the settings back and restart.
Nvidia-users FIX!
After almost giving up I finally tried something with "Shader Cache" and finally it fixed the problem for me and hopefully for all of you with this issue.
(the fix is meant for Nvidia-users, AMD-users can also try this fix, but I don't know where file will be located)
The solution:
Hope that this solution will help you all!
OK so I went to Nvidia control panel disabled the shader cache for global setting and for the game settings, started up Andromeda and loads lightning fast
