Two identical wp-includes directories on server

This is not an “executable directory”. The x means something different for directories:

The execute bit allows the affected user to enter the directory, and access files and directories inside

Source

Also the * doesn’t mean executable for directories hear as you might think if you’ve read that answer.

Instead it is just a directory with the name wp-includes*.

I’m not sure what has happened there but as the folder should be called wp-includes but the second one is called wp-includes* the second one is probably not used anyway.
How that happened? No idea.

Final note – if you remove that directory be careful. * is a wildcard and is expanded by the shell. So you need to escape it.

So use something like rmdir wp-includes\*/.