I'm only receiving pdf files in my dropbox, not the attached ones

Hello,

I've made a form with an upload file option, I've tested that once and again and even made a clone of that form, but nothing appears in the dropbox folder, only the attached pdf (and only some of the pdf not all PDF) file and not any other types like doc or png. Everithing else is working fine in the form, just the attached files not saving in dropbox.

Summary of My problems

The DROPBOX receive only some of the attached pdf   (for example 3 from 10 pdf files)

The DROPBOX not receive any other types files other then pdf like doc or png

Thanks in advance 

We have issues with uploads recently due to an outage on the amazon s3 service. This might have been affected during that time. However, this is now fixed.

As of checking right now, I could not reproduce the problem with Dropbox. All files are sent to my Dropbox account as usual.

My test: