Blizzard has shared a Blue Post, explaining that they are aware of some spells causing crashes, asking players not to use those spells during the raid (Kill Shot has been hotfixed to address this issue). Additionally, Blizzard has added the Teleporter functionality for raids to skip Flame Leviathan, as long as the boss has been engaged once.
Greetings,Just wanted to add a few other issues that we are aware of and are working on fixes for: