Correlation between final-to-initial ratios of the stellar half-mass radii of the barred galaxies and the bar pattern speeds. The colour bar marks the final mass of the SMBH of those galaxies. Those galaxies where the SMBH lies above the threshold of 10⁸ M_⊙ had their AGN feedback switch to kinetic mode. We argue in the text that this correlation is at least partly a result of the AGN-feedback prescription of IllustrisTNG.