A damaged emWave2/PSR can display the symptom of lights that continue to flicker or glow after the unit is shut off.
This is a condition caused by damage to the internal electronics. One of the components in the charging circuit has failed. The good news is that, aside from not holding a charge for very long, the unit should continue to work while charged and can also be used while plugged into the charger or the computer.
Damage of this nature is rare but can occur over time from a variety of means, such as shock (dropping the unit), prolonged exposure to humidity, overheating (left sitting in the sun or left on charger for extended periods of time). Especially plugging the unit into a different charger, even for a split second, can cause all sorts of damage including total circuit failure.
Once again, the emWave2/PSR unit is still usable, just not as convenient due to the inability to hold a charge for very long.