When the issue is induced by aftermarket modifications, no, the OEM is not going to look into it. It’s not their problem, and it shouldn’t be.
There are no wires crossed. When you increase ride height and tire size, you’re changing the entire geometry of the steering and suspension, even if toe/camber/caster are compensated. That includes control arm angle, Steering Axis Inclination (SAI), inner and outer tie rod angles, stabilizer bar angles, unsprung weight, etc. Those variances can produce any number of undesirable effects, including oscillations. This is especially true when operated under severe conditions.
When you have an issue caused by an aftermarket modification, seek an aftermarket solution or return to stock. If this oscillation can be demonstrated to an aftermarket suspension engineering company (Eibach, Icon, etc) using the appropriate equipment, the root cause could be isolated and a corresponding resolution could be developed.