  In this addendum to arXiv:2101.07811 we discuss the implications of the
recent CMS analysis of lepton flavour universality violation in non-resonant
di-lepton pairs for first generation leptoquarks. As CMS finds more electron
events than expected from background, this analysis prefers the LQ
representations $\tilde{S}_1, S_2, S_3, \tilde{V}_1, V_2\,(\kappa_2^{RL}\ne 0)$
and $V_3$ which lead to constructive interference with the SM. In principle the
excess could also be (partially) explained by the representations $\tilde{S}_2,
V_1\,(\kappa_1^R\ne 0), V_2\,(\kappa_2^{LR}\ne 0), \tilde{V}_2$ which are
interfering destructively, as this would still lead to the right effect in bins
with high invariant mass where the new physics contribution dominates. However,
in these cases large couplings would be required which are excluded by other
observables. The representations $S_1, V_1\, (\kappa_1^{L} \ne 0)$ cannot
improve the fit to the CMS data compared to the SM.
