Modifying one array causes the other array to be modified

[Chatouille]

This has to do with how Pure nodes behave vs. non-pure.

Here are a couple posts describing basically the same issue you are experiencing :

Destroy Actor on last element of array not working

[image] The way BP Graphs work, every time an Exec node is evaluated, its input pins are re-evaluated. In case of ForEachLoop you can assume the Array input pin is re-evaluated before each LoopBody execution (and before Completed as well). Since the input pin is a pure function call (Self->GetAttachedActors), it is also re-evaluated. And since you are destroying actor in LoopBody, the result of GetAttachedActors has one less element with every loop check, resulting in skipping every other ele…

How to find randomly selected integer?

All dependant pure nodes are re-evaluated for each exec node. So simply put : [image] This works because here the RANDOM node is dependent twice on the same exec node (print string), so RANDOM is executed only once and its results are cached during this specific evaluation. However : [image] This doesn’t work because RANDOM is executed once for the first Print String exec, and another time for the second Print String exec (giving a different value). Solution : as a rule of thumb, avoid …

On C++ side you normally make pure functions with the BlueprintPure specifier. I’m not aware of the engine doing that automatically for const methods, but maybe that is the case. Did your Filter node become different after removing const (added exec pins) ?