Describe the bug
After installing the BetterPortals mod (https://www.curseforge.com/minecraft/mc-mods/betterportals), mirrors in the overworld no longer reflect the player. They now only work in the nether. When teleporting away from the location of the mirrors, it crashes the game with a null pointer exception (See crash log).

Crash report
https://pastebin.com/ZjGciwLu

To Reproduce
If applicable, the steps to reproduce the behavior:

1. Install BetterPortals with Furnature Mod
2. Create a Nether portal and go through it at least once.
3. Go back to the overworld and place a mirror (Shouldn't reflect properly).
4. Teleport away from the mirror (Unloading the chunk).
5. Game should crash.

Screenshots

Please complete the following information:

• Minecraft Version: 1.12.2
• Mod Version: 6.3.0