As much as I hate answering a question with a question, why does it go away when replacing a blown out damper? Just like replacing any other worn out component.
No. It is what it is and always has been. Its not some sort of witchcraft. Not sure where you are going, but your 50:50 is sort of a relative term. Zero valving in your 50:50 could equal no damper. So

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You didn't get what I told you early in this thread. The steering damper is only suppressing the
symptoms of DW, it is NOT curing the actual
root cause of DW whatever that root cause might be. A steering damper CANNOT shake the front/end or cause the giant oscillations that are DW. The steering damper is a shock absorber, a passive device, it cannot CAUSE anything to shake or oscillate, it can only suppress shake, shock, etc. but the DW shaking itself is always caused by something else.
A new steering damper can only APPEAR to have cured DW but it has only temporarily SUPPRESSED its symptoms until the steering damper wears out prematurely from having suppressed the oscillations/DW it wasn't designed to do. Something else is causing the DW, not the absence of a steering damper or a worn out steering damper. A steering damper can resist shaking and vibration but, again, it's not actually causing that shaking and vibration... something else is doing that... the root cause of the DW which has to be cured whether it be balancing an imperfectly balanced tire or replacing a worn out component in the front-end.
We GET that installing a new steering damper can stop/suppress the symptoms so to some it might appear to have cured the DW but in reality it only temporarily suppressed the symptoms. It didn't actually cure the root cause. And only temporarily because if the symptoms are severe, like from DW, the steering damper isn't going to last long. When the damper fails from DW overworking it the DW will come back because, again, the steering damper did not cure the root cause of DW that is still there.
The root cause of DW is most commonly caused by an improperly/imperfectly balanced tire, especially when something else is loose/worn out like rod end joints, ball joints, loose shocks, etc.. Cure those issues and a steering damper isn't even needed other than to help protect the steering system from jolts, shock, etc.. And. again, a steering damper is a passive device so it CANNOT power the oscillations/vibrations cause by something with power like an imperfectly balanced tire that can really shake the front-end. A steering stabilizer has no ability to shake anything or cure the actual root cause of the DW.