The "yellow triangle" is there because you don't have a Season Pass and as a reminder if you're playing with others that do you'll be kicked out of the lobby when DLC Maps are played.
or could be other way round...my pal joined me but couldnt play bonus maps as he doesnt have them
All other maps loaded will not load those two maps, I have the pass .
Go to this link and verify you have the Season Pass https://account.blizzard.com/overview
Next go to Custom Games and see if they'll load; currently only Casino is missing under "DLC Packs." If you can't load all but 2 of the 3 then make sure your game is updated to Version 126.96.36.19980157 or higher.
To make certain the game is properly updating; Settings window, Game Install/Update .. click Reset to Defaults.
Next try to run the Repair from Battlenet App; Options / Scan and Repair. Never modify the game or Config files. If that fails then clear the Cache and Reinstall the Battlenet App. https://support.activision.com/articles/en_US/FAQ/Deleting-Old-Files-from-PlayStation-4-and-Xbox-One...
The last step is to reinstall the 89 GB of game files. Make certain you have enough disk space and you can certainly back it up. Do not Pause or Stop or Play until the game is downloaded 100%.