Multiplexed LED column driver MOSFET doesn't fully turn off without a resistor parallel to the LEDS
All diodes have a capacitance which reduces with reverse voltage, which does not occur here.  The capacitance also increases with rated power.

This is a very old known issue when multiplexing any LEDs. 

Beware that the Abs. Max/rated current is &lt; 4:1 on most LEDs and in often 1.5:1 in small LEDs.