Quick answer: Construct 3 game in background tab receiving phantom touch events? Page visibility doesn't always pause touch handlers - listen for visibilitychange and gate input.
Mobile player switches tabs; game keeps responding to phantom touches.
Gate on visibility
document.visibilitychange. Set backgrounded flag; touch handlers early-return.
Or pause the game
Auto-pause on background. Game freezes; resumes on visibility.
Test on real mobile
Desktop tab-switching is more reliable than mobile. Mobile background bugs surface on devices.
“Tab visibility is a known cross-platform pain. Plan for it.”
Hidden tab handling: pause game state, ignore input. Surfaces when player returns; restore deliberately.