Can't upload folders

Note, I'm using imgur links as I get following error when trying to upload files:
Jira could not attach the file as there was a missing token. Please try attaching the file again.

Edit:

Uploading a folder should result in this: see here
But this is the result: result

The code at fault is visible here: github

However, deleting following lines results in the folder being uploaded as a 4kb file (size of folder in linux) instead of the folder