Odd issue with custom .json block breaking causing lag/FPS drops

I was testing to see if a new block I was adding got imported correctly and had its correct texture when I found a serious issue with it. When one of these blocks is broken or other blocks are broken nearby them the game just freezes and the reloads after a few second. The FPS readings also go down to a flat 0. The debug and run logs are reporting zero warnings or errors regarding it. All my other .json blocks behave normally and don't do this. What's causing this and how do I fix it?