When MrCrayFish's Magic Mirror attempts to render blocks onto its surface, it starts to probe blocks for properties. I am guessing he assumes something named RedstoneWire will have certain properties and Secret Redstone doesn't have this property at all- after all, it's a block now.
Here's the crashlog, which happened on a server: https://pastebin.com/62yzdZhC
Oh, and the reason I'm reporting it here instead of with MrCrayFish is because I have no idea whether he'll be able to look into his magic mirror rendering.
When MrCrayFish's Magic Mirror attempts to render blocks onto its surface, it starts to probe blocks for properties. I am guessing he assumes something named RedstoneWire will have certain properties and Secret Redstone doesn't have this property at all- after all, it's a block now. Here's the crashlog, which happened on a server: https://pastebin.com/62yzdZhC