Just wanted to say, thank you for having crash reporting switched on, let me discover and fix the most recent crashes in the game (and apologies that you're trying to play and it keeps crashing!) have a 3.6.2 fix on the way shortly
No problem at all, I mean, that's what an Alpha is for after all, isn't it?
The crashes happened after leeting the game run while going afk for a while and coming back after about 10 or more minutes. Reloading the game doesn't solve the issue, need to restart the world from scratch. Maybe this might help you troubleshoot the issue.