Noticed this double click issue with the current version 1.14, confirmed Launcher and my Mac Mini OS is up to date, restarted my computer, tried switching back and forth between full screen and windowed, but the issue having to double click for any left-click action persists and makes the game almost unplayable.
I noticed this issue in my Realms world today, appears it only affected some signs, possibly related to glowing text, came here to see if others noticed this.