This is an issue with the first batch of Octatracks MKII. The inputs works fine when it has something plugged in to it, but when there is nothing plugged in there is noise on the inputs. As most of you don’t use the inputs when there is nothing connected, you will not be affected by this noise but the flickering inputs are annoying.
Contact support and they will help you with a warranty repair.
It has to do with a few components that has the wrong value and needs to be removed. This in combination with tiny amounts of oxide(that will always form) causes noise on the inputs. It’s the combination that causes the issue and neither of them alone will cause this. This is why inserting a cable and removing it sometimes helps as it removes oxide.
It will not affect audio and just affects units from the first batch.