FN keys (brightness, mute etc.) don't work after sleep

When I turn my Inspiron 7537 back on from sleep, the backlit keyboard is on, when I've previously turned it off.

Also, the F keys (volume, backlight, brightness etc.) stop working. I have to re-initiate the FN button settings. I change the Function Key Row option from Multimedia to Function back to Multimedia, this allows me to use the F keys again.