I have this issue too, it appears that the Minecraft Launcher process is still running after closing the game, so you can't open the launcher again (as it is already running).
A temporary fix is to open Activity Monitor, and quit/force quit the Minecraft Launcher process so you can launch Minecraft Launcher again.
I have this problem too, really annoying considering any official release below 1.13 works fine.
It also seems like with some newer versions there's a bug with the player's view teleporting after exiting out of the inventory if you move your mouse in the inventory...
This issue is still present on Launcher version 973 (1), and has not been resolved...