We've now released 1.16 pre-release 2, fixing some crashes. Note that worlds opened in 1.16 pre-release 1 are corrupt and will not work in any way in 1.16 pre-release 2 (this includes using the re-create world button). Please restore an older backup or create a brand new world to play in this pre-release.
Fixed bugs in 1.16 Pre-Release 2
MC-187350 Game randomly crashes / IllegalStateException: POI never registered
MC-187352 Loading a world created in 1.16-pre1 always ask for confirmation
MC-187353 Crash when loading some worlds: IllegalStateException: Lock is no longer valid
MC-187358 Worlds generated in 1.16-pre1 do not have their world generation settings saved correctly, causing chunk errors
MC-187364 Disabling and enabling dimension datapack disables nether and end
MC-187408 Game crashing with Nether portals - java.lang.NullPointerException: Ticking player