Wemos controled LED strip not turning off fully
I think what's happening is that the MOSFET is not completely turning off, working in weak inversion mode. You could try a stronger pull down  - 1k instead of 10k. However, you would need to replace the 1 K with 100ohms to maintain the ratio.  You could also try making this a high side driver.
I also notice you don't have a current set resistor for the LEDs, you may want to add one to improve the life span of the LED string.