[TYPO3] [mit_download] -> Download Repository error -> Site template pasted to the end of every downloadable file

[Makrela Corporation]

Hi there,

I have got a strange error in Download Repository plugin (Typo 3 -> 3.8.0, 
mit_download -> 0.3.5).

Context:
It appeared after moving site from the temporary location (/old/) to the 
primary one (/).

Problem:
Process of adding files and categories runs smoothly - categories are 
created and files uploaded to the server correctly.
But the problem appears when one would like to download file.
To the end of every downloaded file the HTML code from the main (actual 
index.php) template is added.
This naturally makes all downloaded files corrupted (the files on the server 
are ok).

I have no idea what is going on and how to deal with this issue.
I hope that you can help me fix this problem.

Best regards,
Michal Szostak