Nuclear modification factors $R_{\rm pPb}$ (left) and $R_{\rm PbPb}$ (right) of electrons from beauty-hadron decays in comparison with different theoretical predictions, see text for details. The vertical bars represent the statistical uncertainties, while the boxes indicate the systematic uncertainties. The normalisation uncertainty, common to all points, is shown as a filled box at high $p_{\rm T}$ for both collision systems.