Comparison of the traces of the NW arm-like structure measured in the 2015 (green) and 2021 (red) data sets, with the predicted location of the trace in 2021, assuming respectively a rigid-body rotation associated with planet c (solid blue) and a local Keplerian velocity at 70 au separation (dashed blue). The points with error bars correspond to the mean radial position measured at each azimuth on all data sets acquired in 2015 (two ADI data sets) and 2021 (two PDI data sets), while the solid lines correspond to a fit of the data points with a third-order polynomial. The error bars take into account both the standard deviation of the measurements and the radial uncertainty of the Gaussian fits used for the local maxima detection. The blue shaded region around the predicted 2021 trace corresponds to the uncertainty on the planet orbital parameters of Mesa et al. (2019).