The difference between players rated 1800 and 2000 seems so huge.

1900-2000 it's the same it's from 2050 that we feel the difference

In Blitz there seems to be a psychological bump at the hundredths starting from 2000, maybe 1900 too.
i'd go look at the stats..
lichess.org/stat/rating/distribution/blitz

The theory is that there is a celebration lull... But it maybe be something more mystical.

Edit: thinking back at the "theory" of the resting after hundreth reach... Since glicko is more data responsive to the actual distribution of game being paired in a dynamical sense (volatility modelling), such a lull would have likely a signal left in the statistics for fast enough time controls. did lichess plot the corresponding deviation statistics, ever?