OP-Z distorted output?

Hello,

Just this week I have noticed that my OP-Z might have started distorting a little. Is this a known issue?

I noticed with only a kick and organ playing. I have cranked down effects. Master track has no chorus or drive, and mixer has drums and synths both set to 60, punch at 15 and if master volume (on mixer page) is at 70 it is noticeable but not at 50. I have always had the master volume at 70 so this is new to me.

I think it can be heard on the usb recordings too not just headphones jack.

Has anyone else suddenly had this happen?

This is the audio recorded using USB (which is a bit flaky)

The distortion is just noticeable with the kick coming in at the start of a bar. Mixer page master volume set to 70.

Now below is the same pattern but with Mixer page master volume down at 50 and the distortion disappears. I’m sure this didn’t used to happen.