Ok hopefully it's software and will be fixed lol But honestly I'm 99% sure it's hardware. Just the nature of the knob L6 has chosen. Another argument for hardware; have you ever pushed a button on the Go (Page, footswitch, etc.) and had the software 'bug' and not do the action? Plus there's basically 3 screens used by that rotary knob;
switching patches
scrolling through your effects chain
scrolling through effects when editing a block
And all of these show the intermittent rotary knob issue; if it was just one screen when scrolling very fast and hitting DSP limit, ok, but yeah the odds are extremely low that there's a software bugs in all those screens which just happen to coincide with this particular knob...!
And the 2nd knob has the exact same issue, the one used for scrolling up/down in effects, etc. So yeah, I'd say 99.9% certain it's hardware. L6 should know, but the support tech likely doesn't have the answer on scrip, but for sure their QA must be well aware of the issue.
Another proof it's hardware; again, just navigate left/right on your effects chain, that has zero impact on any setting and isn't altering anything, yet you'll still get a ~10% knob failure rate. Now do the same with each footswitch, which actually impacts effects, modifies lights, also move the selected block in your chain, you'll get 0% failure rate. 99.99% certain it's hardware. ;)