I booted up a world to try out the new snapshot.  After playing for a few minutes, the game crashed and I received this error.  I attempted to run it again a few time, sometimes crashing immediately and sometimes after a minute or so.  I received this error message with it:

The game crashed whilst exception ticking world
Error: java.lang.AbstractMethodError: bxx$$Lambda$1052/160479339.a(Lcom/mojang/datafixers/Dynamic;)Ljava/lang/Object;

I also attached the crash log I received.  This occurs on multiple worlds running on 18w48a.  Hoping whatever is happening is easily fixable, looking forward to checking out the new village features.