What did your tuner report as the cause of the high knock? Yeah the clutch can cause a lot of noise
I know what u mean about high knock caused by the starter motor, it must be the starter pinion engaging with the flywheel, mine has shown 120+ on start up so I religiously reset my peak values after start up.
I know when mine has hit high knock in 3rd gear and literally only flickers the engine light on the dash, like a quick spike. If it stayed on continuously I'd be freaking out