Having the same non appearing of the action icons as others posting here. It happens about 50-60% of the time when the game loads or reloads a mission.
I know when it will happen because the mission briefing doesn't come up up after choosing it - instead the game just sits waiting for you to click anywhere on the screen and then it goes into the game with the UI invisible but still clickable if you can hover over the spot previously learnt.
First time I played HED I had no idea the invisible UI had happened cause I knew no different - but after restarting the mission (I failed) and bammo there are all these options like firewall to click on lol - made the game much easier
Quitting mission and reloading profile with 3-4 attempts usually gets the UI back at functional.
Good luck with the fix! Am enjoying this game - the previous iterations of Hacker Evo did my head in lol, very much enjoying the changes so far.
Btw way I am running this with Windows 7 - 64 bit OS @ 1920 x 1080