Problem uploading files while adding expert

On the add an expert page, when I click add button to attach a file, a pop opens up saying choose a file. When I click choose a file my media library opens up, and when I select any file and click select, the file does not gets added.
When I click the add button again, there it is, the file which I selected before is already selected and when I click submit button, the file gets added.
Please help me get through this issue
Here is the link to add an expert page