I had the same problem with sound and brightness hot keys after upgrading to Ubuntu 18.04 on a Lenovo P50 using Unity.
Park Ju Hyung (arter97) solution #11 worked for me but with a slight modification:
ExecStartPre=/bin/sleep 1
Otherwise the hotkeys worked but the fonts began to fade making the text unreadable in all applications.
I had the same problem with sound and brightness hot keys after upgrading to Ubuntu 18.04 on a Lenovo P50 using Unity.
Park Ju Hyung (arter97) solution #11 worked for me but with a slight modification:
ExecStartPre= /bin/sleep 1
Otherwise the hotkeys worked but the fonts began to fade making the text unreadable in all applications.