I haven’t seen an explanation. I think it’s more surprising than the slides suggest, because if you look at the IERS charts there’s a clear change in the dX and

I haven’t seen an explanation. I think it’s more surprising than the slides suggest, because if you look at the IERS charts there’s a clear change in the dX and dY plots in about 2019, corresponding to a change in gradient of UT1-UTC. https://datacenter.iers.org/plots.php?id=6 https://datacenter.iers.org/plots.php?id=6