Upon joining into a server on 1.17 approx 50% of the time the world fails to generate for the player and the player simply falls through the world until the connection times out, on other attempts world load is instant.

Once the player successfully connects then no issue. Same settings as we had for 1.16 which was fine. Affecting players from multiple locations. No issues with the server that I can see, keeping up with the tick rate fine, network connection is stable.