Contact Form 7 – How to trigger 'File type not allowed' Validation Message

I’m using Contact Form 7 on a site and it’s working correctly –

However the form has a file upload field, which is configured to accept only doc and docx file formats. When a user enters a non-accepted file-type – such as jpg, they receive the generic message:

‘Validation errors occurred…’

but I would prefer the user to receive a more accurate message informing them that only doc and docx file-types are allowed.

I thought this was the functionality out of the box but it does not appear to be working.

Here is the short-code that I’m using to generate the field:

[file* file-262 limit:2000000 filetypes:.doc|docx 15/]

Any ideas how I can trigger a more accurate validation message?

Thanks!