Shebang can reference a script in Linux

I've always heard that the target of a shebang line (e.g. #!/bin/bash) must be a binary executable, not a script. And this is still true for many OSes (e.g. MacOS). But I was surprised to see that this is not true on Linux, where up to 4 levels of scripts can be used, where the fourth script references a binary executable in its shebang line. However, if 5 levels of scripts are used, then the program will fail with the error Too many levels of symbolic links. See the LWN article "How programs get run" and the following code which was not shown in that article.

$ cat wrapper2
#!./wrapper

When did this change occur (assuming that at some point it was not allowed)?