Epoch 17, 2009 December 03. a) Core spectrum, where Qa represents the core and Qb the feature moving downstream. For comparisons, see Figure 4c. Core-shift vectors of all frequency pairs using b) Qa and c) Qb. Similarly, as in the previous epoch, the two components have a similar impact on the direction of KQ core-shift vector. Power-law fits (red curve) using d) Qa and e) Qb. In this epoch the flare appears to hinder the correct location of the core at the Q-band (43 GHz). This ultimately disrupts the core-shift effect by increasing the core-shift values at the high frequencies, as seen in d). Therefore, this observation is not included in the variability analysis of index k_r.