There was a serious lag when loading the world.

Note: This problem seems to be partly related to the lag in logging in Microsoft account.

This question is partly related to the https://report.bugs.mojang.com/servicedesk/customer/portal/6/MCPE-219619.

Steps to reproduce the issue:

Using any beta version of 1.21.90 to load any world, you will find that it takes much more time to load the world than usual. This problem did not appear in the official version of 1.21.80.

Expected result:

It should take a short time to load the world, instead of an error after loading for 1 to 2 minutes.

Actual result:

Loading the world took too long and an error occurred.