low pass filter with cutoff all closed

[matpo]

try to play a note only with sub osc (-1 octave),without kbd tracking,without ENV amt,
i pull the cutoff from the center position to the left, at almost 10 oclock i can't hear anything,
i hear an high frequency note with a very low volume,from 10oclock to the extreme left.

is it a problem?

[matpo]

Please,Someone tell me if it's right or not,and why it's like this

[Bruno@arturia]

can you still hear it with all waveforms at 0 in the mixer?

[matpo]

No,it does only a "click" sound with all waveform to 0 and all the two envelopes to 0a 0d 0s 0r,but don't hear high pitch noises of waveform anymore

[Bruno@arturia]

and with only Sustain at max, all other sliders at 0?

[matpo]

with only sustain at max,and cutoff knob at 0 (all closed) LP,i can hear high frequency coming from Oscillator