Out of nowhere a new issue has popped up which is teleporting players up into the sky and dropping them to their death. FUN! I spent a good chunk of yesterday and today trying to track this down. I have pushed an update with a temporary solution as well as some additional debug logging. Instead of being teleported into the air you will now simply pass through the block. This should only happen on single slope blocks. Here is what it should look like while passing through a single slope block. If your character doesn't move vertically while going over the block then please take to this forum thread and post your logs.