Clusters with a orange triangle and a black and gray diagonal stripes pattern

Hi all, I have some scripts I made on an other computer, and some scripts I worked on, but were done by someone else. Now when I try to use them on the new computer, I have some of the cluster components (almost all of them) with a orange triangle on top and a diagonal stripes pattern. They still work and if i click on random parts of them I can still open them.
My question is: what is this error? If someone can tell me the name, I can search some material on my own, the problem is I don’t even know the right keywords to search documentation about it.

Thanks in advance!