I'm not entirely sure very much about the bug right now because I can't open the world without crashing anymore. But I think it was interacting with vines that caused it? Because I had tried to place a block on top of vines before, (the new moss carpet block if that's helpful in any way) but every time i tried, the game would crash. I could do other things such as fly around, place blocks on other blocks etc. I tried climbing up some vines, but that caused a crash too. And now whenever i open the world it just freezes up for a few seconds and then crashes. This didn't happen in a blank world when I tried a similar setup.

I don't think the screenshot is very helpful, but I included it anyway~