Hotkeys in Mac version of Unreal don't work well

Reply a year later because your question came up first on a Google search and it took me a while to figure out the answer:

Just RESTING your fingers on the Mac track pad is treated as a right-mouse click and puts QWEASD keys in move camera mode. If you completely remove your fingers from the track pad you can then use these keys for regular shorcuts (select, translate, rotate, etc).