Honestly, I think I need to retire that node. It hasn't been updated in ages and there are some known issues. I'd always intended to expand on it and create a small suite of utility nodes but I'm afraid that uibuilder kinda took over my available development time!
So I wouldn't recommend using it now.
Because the function node now supports npm modules, I would recommend using fast-glob if you want to get a list of files into a msg.