Problem With Downloads- Watermarks On Clean Replaced Images.

I recently have had a problem whereby downloads from the site have my watermark across the centre, it does not happen if I download the image from the order, but happens when my client does.

I have today had an order where I replaced the images with clean no watermark on them.  I ensured that when I uploaded them that the uploader did not add either the watermark or a logo.  However when they downloaded them they had a very faint watermark across them.  I am at a loss as to what to do to stop this happening.   I really want my clients to be able to download from the website as I get to know when they downloaded, yes, I can send via email, or Dropbox or WeTransfer but I need to be able to trust the website as sometimes I may be away from my office/home working and will not have access for urgent orders.

Can anyone please help?

Sounds like you have a watermark set for your download product. This is the only way it will add a watermark to the purchased download. 

Edit the download product being purchased in Photo Products -> Product Base and remove any watermarking options.