Noise in all 4 Mic ports on the UR44C

Hello everyone!
A few days ago I got a UR44C and I’ve been happy with it since. Today I noticed a noise coming from input 1-4. I can hear it when I plug my headphones into line out 1l, 1r, 2l or 2r. When I mute input 1-4 in dsp the noise is gone. I also hear noise when I plug the headphones into the headphone plug and:

  • I crank the Headphone Knob all the way up
  • I turn up any of the gain knobs to like 3 o’clock or higher
    Or when I plug the headphones into master output and turn the master output knob all the way up.

The noise is not very loud and gets drowned out by instruments or microphones.
I just wanted to ask if this is normal or I have a faulty device.

Thanks in advance,