So this happens in every mode at diferent times of the game. I won't be able to click, select or use abillities on any units (enemy, ally or my own), buildings, points or items (like wargears, ressources or boxes in the campaign) on a certain area of the map. When I try to do so my left click will only react if using abiilities that target the ground (like granades or attack ground) while my right click will make any units I have curently selected move to that position. The only way I figured out how to mitigate the problem is by zooming in on the thing I'm trying to click and that can require my camera to zoom in far too close to the ground for me to be able to select things properly. Sometimes the glitch will go away but it might also happen again at a different location before the game is over.