Re: Screen glitching at startup *update*
Recently I reported an issue with the screen glitching at startup since upgrading to Mojave, usually resembling static from an old TV for a split second. This is a bug that occurs if your screen is set to a scaled resolution and Apple is currently investigating it. From Randy at Apple Support:
"This issue is currently under investigation, but doesn't represent a hardware issue. Some users have been contacting us in regards this issue, and we are working on solving it in coming updates, if this only happens after waking or startup, we recommend to keep your Mac up to date, in the coming updates this issue should be solved."
MacBook Pro with Retina display, macOS Mojave (10.14), Late 2013