AirPods 4 ANC ringing/blinking when moved

Hi everyone, last week I bought a pair of AirPods 4 ANC from Amazon. Overall I’m really happy with them, but there’s one thing I can’t figure out. Whenever I pick up the case while it’s not connected to any device—especially if it’s been sitting for a while—the case suddenly starts ringing and the green light blinks, almost like the “Find My” feature was triggered. Has anyone experienced this? Any idea why it happens?