When I updated the server version from 20w22a to 1.16 pre1, I found "the_end" is much darker than before. So that I create a whole new server world for test, but its "the_end" is still darker than the old version. In the other hand, in the world I create at local, "the_end" has no problem. That strange thing only happens in server.

The same thing happens in 1.16 pre2 too.