a) Average 6.7 GHz maser line profile of G22.357+0.066 (blue line) with the variability index VI₁ superimposed (red dotted line). b) Folded flare profile at 80.1 km s^-1 feature. The dotted line represents the best fit to the curve. The symbols mark different cycles. c) Time series for the 80.1 km s^-1 feature with the best-fit curve superimposed. The arrows mark the dates of the EVN observations. The residuals from the fittings in b) and c) are shown by the crosses.