No it isn't. That's a player problem.
You get taught in practice from High School as a Safety how to read your keys. Every week in film session the DC & your position Coach will run down the scouting report of the team your facing & literally break down the plays they run & tell you what to expect. Then in practice, they will drill it over & over again what you're supposed to do in specific situations against specific plays.
If a SAFETY doesn't have his eyes on the QB, then that's 1,000% on the Safety. As a Safety, you literally have no other responsibility than to watch the QB on every single play & adjust according to what happens pre & post snap.
How on Earth could that be a Coaching problem if watching the QB is literally apart of your job description as a DB???