Respawns In A World With No Blocks And The Sun + Moon Are Together

So On Minecraft JAVA Edition On The Latest Snapshot At The Time Of This Post (18w44a), me and my friend found that when either of us die, when we click respawn, it doesnt work at first but then after about a minute of spamming respawn, we respawned in a dark world with no blocks anywhere, we switched to creative and could not fly, could not land, but when we look up we saw the sun, but when we looked down we saw the moon below us.I told him to quit my server and try killing himself on a single player world and he he and I both did and it still continued to happen except when I tried it for the third time, it was a light world and instead of both the moon and the sun, there were 2 suns!!!! PLZ FIX