Charging case of AirPods Pro 2 (2nd generation) beeps and flashes orange despite being charged

After not using my AirPods Pro 2 (2nd generation) for about a month and a half, the charging case started emitting a low-battery sound and flashing orange, even though both the case and the earbuds are fully charged. In addition, the usual chime indicating that the case is charging no longer plays—regardless of whether the earbuds are inside or not, and whether I place or remove the case from the charger. The “Enable Charging Case Sounds” option is turned on in the settings.

I tried resetting the AirPods by following this official Apple guide, but the white flashing light never appeared during the process.

Strangely, my AirPods Pro (1st generation), which were stored in the same place, don’t show any similar issues.

Could storing both pairs next to each other for an extended period have caused this issue?