Since Badspot made the new launcher that makes packets more efficient I have been crashing a lot more lately.
I figured out that when the player's connection was slower they would crash less because they would download the new sky and delete the old sky all at once, making the transition more seamless.
Now that the packets are faster they will delete and create the new objects separately, causing them to crash due to not having a sky for the fraction of a second that they have to download the new sky.
Since the new launcher was released you will now see the sun go away for a second, and everything go pitch black for the same amount of time.
I fixed this by putting a 100 ms delay on deleting the old sky.
I also added support to allow different skies for every minute, instead of every hour (in game hours). Now there can be as much as 60 sky changes per hour. Making the transitions between day and night much more seamless.