Thank you for your input, starball. Funny story, I tried to troubleshoot the keybindings and whilst doing that, I somehow opened my settings.json file. There I could see that whenever I hit "'" key the last line of settings.json was removed or added. That was the multiCursorModifier. I thought omg, this is crazy the key was in the keyboard shortcut settings. I assigned a different key combination to it and the problem was solved.

Without your input that wouldn't have happened. So thank you so much.