Custom Block add-ons crash the game!

I love using add-ons in my worlds, but the latest update has kind of made it impossible. It's not even with the item add-ons, it's the block add-ons in particular. Every time I load a world that has one installed, the game says "Loading Resource Packs", but then the screen goes white for half a second, and after that the game crashes! Could someone please fix this? By the way, the block mods that I tried all have glowing blocks, so that may be a helpful factor to fixing this bug.