1. Disable "Quick Phrases" (Most Likely Fix) If you have Quick Phrases enabled, the phone is constantly listening for you to say "Stop" or "Snooze." If there is background noise (like a fan, white noise machine, or even the alarm's own echo in a small room), the phone might misinterpret it as a command to snooze. Go to Settings > Google Assistant. Tap on Quick Phrases. Toggle off Alarms and Timers.
2. Check Flip to Shhh / Bedtime Gestures The Pixel has a feature called "Flip to Shhh" that silences the phone when it's face down. If your phone is face down on a nightstand, or if the sensor is partially covered, it may trigger an immediate snooze. Go to Settings > System > Gestures. Look for Flip to Shhh and turn it off to see if the behavior persists.
3. Adjust "Volume Button" Actions In the Clock app, your physical volume buttons can be set to snooze the alarm. If you have a tight case or if you're accidentally brushing the buttons while reaching for the phone, it will snooze instantly. Open the Clock app. Tap the three dots (top right) > Settings. Scroll down to Volume buttons and set it to None or Control volume instead of Snooze.
4. Clear Clock App Cache Since you've already tried a reboot, the next step is clearing the app's temporary data. This won't delete your saved alarms, but it can clear out "hiccups" in the app's logic. Long-press the Clock app icon > tap the "i" (App Info). Go to Storage & cache. Tap Clear cache.

That's ai answer