Bandwidth versus measured RM for a selection of bursts detected on MJD 59243. The bandwidth is shown as error in y-axis, while x-axis error refers to RM error. The red line is the inverse variance weighted RM average. Bursts have been selected such that they occupy around half of the entire observing band. The observed trend is non physical and caused by DPHASE deviations from the linear model used to calibrate. See Sect. 2.2.