There are certain characters and filenaming conventions that are used by the OS or server software.
That looks like a cut and paste from Dropbox’s file naming protocols in order for them to transfer data across servers to get it to you.
Even on macs, you are not supposed to use those characters you are told to avoid.
A lot of my clients like to use government style file ID numbers that are something like Graphic.3.4.5.indd.
I have to either retype the file name or click on it in the folder to save-as because the program does not recognize anything as a filename beyond the first period following Graphic. It used to be, Indesign did not recognize image links if they had periods in them.
Because they are on Macs, they inadvertently use #, & and * all the time and sometimes only half of their packaged files get picked up by the software.
What you really want to avoid is a backslash. That is an OS command level notation that can cause all sorts of wonderfully weird and wacky things to happen to your files. Do NOT write the date in your files using backslashes. Or periods.
Using spaces is pretty much ok, except for some servers.
The cap letters, some OS recognize them, some don’t. The ones that don’t will cause a file conflict if two files have the same name but one is capped.
When working anywhere that might be cross platform, and that includes handing off for print, work to a lower common denominator.