Hi js0028,
It sounds like you're having an issue with random vibrations in StandBy. If so, be sure the following conditions are met, specifically keeping the device stationary. The steps below found in the article here can help: Use StandBy to view information at a distance while iPhone is charging
"Start StandBy
- Connect iPhone to a charger and set it down on its side, keeping it stationary.
- Press the side button.
- You can swipe left or right to switch between widgets, photos, and clocks. Swipe up or down to scroll between options for each of these views.
- When Night Mode is on for StandBy, the screen adapts to low ambient light at night and displays in a red tint so that it’s not intrusive while you’re sleeping.
With the Always On display (on iPhone 14 Pro, iPhone 14 Pro Max, iPhone 15 Pro, and iPhone 15 Pro Max), StandBy stays on to show useful information. For all other iPhone models, it’s easy to bring up StandBy anytime by tapping the screen, gently nudging the table your iPhone is on, or using Siri.
In each location where you charge iPhone with MagSafe, StandBy remembers your preferred view, whether that’s a clock, photos, or widgets. This means you can have it set up for family photos in the kitchen, or an alarm clock at your bedside."
You can also double check your settings with the steps here: Change iPhone sounds and vibrations. However, if your device is fully updated and you've tested a normal restart and with a different charger and the issue continues, reach out to Apple directly to report it and further assist. Get Support
Best.
