Why: You're feeding an Array<{elem}> into a function that expects Array<{other}>. UE5 doesn't auto-cast array element types element-by-element — you'd lose type safety.

Fix: Either: (a) change one array's variable type to match (My Blueprint → variable → Details → Variable Type → set to Array of {other}), or (b) loop over the source array, cast each element individually, and Append to a new typed array. Use the ForEachLoop node for this.