When travelling dimensions, there is a chance the player will be sent to an empty void and the message "Waiting for chunk..." will be in place of the biome info in the debug screen.

Workarounds:

• Reload the world

Updates:

This issue seems to be most common switching between dungeon dimensions and pocket dimensions.

Likely an issue with lazy pocket generation. Any info on this is useful. Whenever you experience the freeze, please note down the pocket which is being generated. (See log files)
There are two possible causes here:

1. Someone set a pocket that is using redstone or another block that would update it's neighbours on placement to generate lazily. There is a high chance this will cause a freeze
2. Lazy pocket generation has a chance to cause freezes. Possibly related to the performance of the client/ server.