Files with % inside the name not available

I can't understand why if I upload files with names like abc+fd+ds.png are working fine, but if I publish files like abc+4+%2b24bd.png are not available, I can see only the message ERROR 404 - Not Found!
Every time there is the symbol % the files are not available
Someone have idea why happen this?

 

Internet search engines found this
https://en.m.wikipedia.org/wiki/Percent-encoding

 

Thank you about your help