Fan PWM signal not in compliance

[wolframalexa]

Problem
Users cannot use a fan, because the fan PWM signal is not in electrical compliance.

Observed Behavior
GPIO14 provides a nice PWM signal, but the signal becomes less crisp as it goes through the level shifter. In both images below, the blue line is the FAN_PWM_LS node. Yellow: left = GPIO14, right = FAN_PWM_INV.

The transistor Q3 should invert the PWM signal, but does not appear to do so.

Root Cause Theory
At 20kHz, it is unlikely the fan signal is switching too fast for the transistor. It may be due to a transistor misalignment; switch from the DMN26D0UFB4-7 to the DMN26D0UT-7, which is in a larger SOT-523 package, to avoid misalignments.

Suggested Next Steps
Ask a more experienced engineer. May need a larger pullup, or more power control.

[wolframalexa]

Removed Q3 and measured the fan PWM remaining high - showing that this is likely due to a transistor misalignment. Will switch to larger package for A01.