Strict weakness of RCOLOR_2

Determine whether the Ramsey-type graph-coloring principle RCOLOR_2 is strictly weaker than the Ramsey-type weak König's lemma principle RWKL over RCA_0.

Background

The principle RCOLOR_k asserts that every infinite, locally k-colorable graph has an infinite k-homogeneous set. For every k at least 3, RCOLOR_k is equivalent to RWKL over RCA_0. The cited work established that RCOLOR_2 has the P_1 property for measure, but the reverse-mathematical strength of the binary-color case remains unresolved.

The open issue is whether the exceptional case k=2 yields a principle strictly weaker than RWKL, rather than merely being another equivalent formulation of it.