When attempting to download on any version above 1.21.4 while the player has gained statistics related to a version above 1.21.4, the player will disconnect with the error Failed to decode packet 'clientbound/minecraft:award_stats.
Wouldn't be a big issue, but this crash still happens when player/statistics/entity download are disabled. Disabling everything and then attempting to download also results in the same crash.
Only fix I've found so far is to reset the playerfile, but on servers that have run for many years this means you are removing years worth of progress from your account.