Device Settings > Notifications > App notifications > Drunkenstein
Device Settings > Notifications > Do not disturb > App notifications > Add App > Drunkenstein
This can happen if battery settings for Drunkenstein are set to optimized or restricted, or the app is on a deep sleep list, or you might have a memory/battery manager app restricting Drunkenstein. This can result in Drunkenstein notifications first being delivered when you unlock your phone, and you might get a bunch of notifications that was all delayed
You can find more info here on troubleshooting delayed notifications link