I've been using a mac book pro late 2013 with an Asus proart display monitor connected by Philips HDMI cable with no adaptors for over a year now.
Only recently I got a weird behavior that happens sometimes. My external monitor sometimes don't get signal from mac book pro during cold boot process, I found a workaround that simply is to reboot the system from the login menu and then I get the signal on the booting process and it works non-stop like nothing ever happened.
I'm not bothered by my workaround, my only concern is if it could be an hardware issue and I'm not sure since it seems to work well after a reboot with no problems.
Display has no energy saver turned on. I've reset nvram and smc OS: High Sierra 10.13.6