Intrinsic Scalar-Tensor Decoupling as a Mechanism for the Dual Behaviour of Cluster Subhalos

This short theoretical note proposes a scalar-tensor interpretation of the radial duality reported by Natarajan, Chiang & Dutra (2026) in massive lensing-cluster subhalos: collisionless-CDM-like outer truncation radii, but enhanced inner lensing efficiencies usually modeled as requiring very steep effective inner slopes. Within Entangled Relativity, deviations from GR are governed by the local matter-geometry imbalance Lₘ - T. The note argues that high-dispersion subhalo cores can activate a scalar relay, while pressureless outskirts remain effectively GR/CDM-like. A Jeans/NFW estimate in a MACS J0416-like environment shows that the density-weighted relay source is concentrated in the inner few kiloparsecs, near the scale of the reported GGSL anomaly. The manuscript identifies three falsifiable predictions distinguishing this mechanism from velocity-dependent self-interacting dark matter.