I'm at crisis level 2. I have an opulence cargo ship over a planet owned by a neighbor I have a commercial pact with. When I select the option to establish the branch office, the cargo ship charges up the creation of a branch office, but on 100%, it concludes and there's no branch office on the planet. There's no existing branch office on the planet, and I could put a branch office there normally if I wanted to.

I haven't been able to reproduce this in testing. Are you using any other mods?

Nope. No other mods.

Does a notification pop up which claims it was successful?

No. No notification.

I've figured out what causes the bug. If you order a cargo ship to deploy an orbital branch office and then cancel the order, attempting to give the order again will cause it to fail.
You can work around this by targeting another planet and ensuring the order completes or using a cargo ship in a different fleet on your original target.

I'm not actually seeing the Ascension Perk for Monopolist in the full list. I have a "few" (30-40) mods turned on so some of them may be affecting it but I'm not positive on trying to figure out which.

I checked Steam\steamapps\common\Stellaris\common\ascension_perks\00_ascenscion_perks.txt and I didn't see a reference to monopolist anywhere and the normal Galactic Nemesis perk looked about the same

Looking in Documents\Paradox Interactive\Stellaris\ I can see references to Monopolist in some files, but can't pin down where it may be at

I checked the debug menu in game and can't find any sort of ap_monopolist ascension perk I could manually activate either

Assuming there are no conflicts with your other mods, for the Monopolist Ascension Perk to show up all the following conditions need to be met:

• Have the Megacorp DLC enabled
  
• Have either the Nemesis or Machine Age DLC enabled
  
• Have the Corporate authority type
  
• Not have the Criminal Syndicate civic
  
• Not have taken any of the Cosmogenesis, Galactic Nemesis or Defender of the Galaxy ascension perks.

The script name for the ascension perk is jam_mcp_ap_monopolist, and you will have to check Steam\steamapps\workshop\content\281990\3419898929 to find the files included/edited by this mod.

Aaah; that did it. I had the Criminal Heritage civic which caused it to be disabled and hidden. Started a new game with different civics and confirmed I could see it in the full list of selectable Ascension Perks. So good news; no conflicts in selecting with any of my mods. Thanks!

I cant find the trade policy option anywhere

The trade policy should only be available for non Monopolist empires who either have a commercial pact or are in a federation with a Monopolist empire.

Why wouldn't the trade policy give the resources to the monopolist?
Though thank you for clarifying it. Thought my game was broken :P

My current idea for the trade policy is to act as if the Monopolist is supplying its trade partners with resources. Combine this with the Local Stock Management branch office building and you can make other empires reliant on the trade policy to remain productive.

I did test having a trade policy for the Monopolist but I didn't like how one dimensional this made their economy so I replaced it with bonuses to their jobs base resource output.

It might just be my mod list, but the Monopolist Trade Partner policy doesn't seem to be showing up for those I have a commercial pact with. I even tried tagging into their nation to check, and they don't have it available at all.

Going to check with just this mod to verify.

If any of the other mods you're using add or modify trade policies, that could cause compatibility issues.