I couldn't initially reproduce the issue playing the file with MIDI sent from Cakewalk via physical MIDI loopback path to standalone Pianoteq 8 so it would appear as real-time MIDI input, But then I started experimenting with lower durations and found that very short, soft notes would not consistently trigger the key noise. With the velocity of all notes reduced to 2 the key noise became progressivley more intermittent below a duration of 120 ticks (960 ppq at 120bpm) until it was pretty consistently missing below a duration of about 100 ticks. I thought this might be related to Pianoteq's modeling of repetition level function, but the notes aren't close enough together to be considered a repetition (start times left at the approximately quarter-note intervals in the file). The sme thing happens with the Pianoteq 8 VSTi hosted inside Cakewalk with MIDI routed directly to it.
But, again, I don't hear the problem with notes of longer duration as in the original MIDI file regardless of velocity.