On Pixel 10 Pro (Android 16 / SDK 36), when media is playing on the speaker and a notification sound plays, the audio route switches from speaker-safe to speaker when media resumes. speaker-safe applies additional DSP limiting and is quieter; the switch to speaker causes a noticeable volume increase at the same volume setting. The route is never restored to speaker-safe.
When using the phone to play podcasts or sleep sounds at bedtime, the volume suddenly increases after the first notification arrives (typically 10-15 minutes after locking the screen), waking the user. Reproducible across multiple apps (Podcast Addict, Headspace).