In addition to what @TheJamsh wrote, you could try disabling motion blur (if you have one) and try this change too:
SMAA – Subpixel Morphological Antialiasing integration - Rendering - Epic Developer Community Forums. It helps a bit with visible lighter ghosting but it doesn’t cure all ghosting, could be still enough for your use case.
There’s also been some this fix to Temporal AA on master and 4.15 branches on github (could worth checking out when 4.15 previews get out):