In this work an electric-field gradient and magnetic hyperfine field study of the multiferroic AgCrO2 triangular spin lattice is presented. Perturbed angular correlation measurements at different temperatures, revealed the coexistence of two electric-field gradients, i.e., two distinct local environments at temperatures below 100 K. The emerging second local environment appears as a distortion of the Cr surrounding resulting in a local symmetry lowering. This local distortion emerges much above TN and concomitantly with the onset of short-range magnetic correlations. We claim that, through a magnetoelastic instability, distinct Cr-Cr exchange interaction pathways appear providing a channel for magnetic frustration release.