Article written by Euan C.
Description : Array types are currently not supported with property access directly on animation nodes
Potential Impact: Limited: Anim BPs that attempt to use property access to set array types will fail to compile with a check failure in FPropertyAccessSystem:PerformCopy()
Solution: The issue will be resolved in UE5. The workaround to use property access for these variables is to use the Property Access node to get the values.