If the material of an always-on Stargate is changed, it is disabled during loading instead of being updated to the new material. The Stargate is no longer usable, and a warning is displayed in the console for every Stargate affected.

Steps to reproduce:

1. Build a bunch of always-on Stargates using the nether.gate format
2. Stop the server
3. Change the open iris material of nether.gate to END_GATEWAY
4. Start the server
5. See a bunch of warnings, and notice that all Stargates have turned into normal nether portals