Following Day 2 of Workshop | Rigging in Unreal Engine | Talks and demos
In the video, there seems to be a really useful way of creating bone array variables by promoting it. However, in 5.8, when renaming to what it should be its actual name, it empties bone arrays and overrides existing get variable nodes name (disconnected and in sequence)
Also, when creating and filling the variable array manually, if you try to change it of category, it empties all the variable arrays.
Solution: Connect the constant arrays, and duplicate it in every part of the graph