DIAGNOSIS Residual charge is stored in the tool's capacitors, likely related to the LED circuit. It's a known quirk, not typically a malfunction.
FIX It will dissipate on its own. The dim glow will fade completely after a few minutes as the capacitors discharge. To instantly clear it, briefly touch the battery contacts on the tool together with a metal object (like a screwdriver blade) to safely short and discharge the circuit. Do this ONLY with the battery removed.
IF THAT DIDN'T WORK If the light remains brightly lit for more than 10-15 minutes with no battery, there could be a fault in the switch or control board. This is rare.
HEADS UP This is normal behavior for some units. It does not indicate a parasitic drain that will kill your battery when attached. The glow is from leftover milliamps, not active power draw.