Why are images uploaded to main domain, when using multisite with different domains?

I am using Worspress Multisite feature, where I have two domains:

lkrnac.net -> main domain

handysvandy.net -> secondary domain

Not using any special plugin to handle multiple domains.

In Network Admin area I have two sites registered with two mentioned domains. Also have “Path” set to root (“https://wordpress.stackexchange.com/”) for each site and checked “Update siteurl and home as well” check box.

Everything works generally fine. The only problem is that when image is uploaded for secondary domain (handysvandy.net), it is uploaded and served from main domain (example: http://handysvandy.net/2014/06/12/dandelion-and-parsley-salad/).

What should I do to have images served from and uploaded to secondary domain?

EDIT – source

I followed this blog to set up domains for multisite:
http://kaspars.net/blog/wordpress/wordpress-multisite-without-domain-mapping

EDIT2 – example links

Post

• http://handysvandy.net/2014/06/12/dandelion-and-parsley-salad/

Images

• http://handysvandy.net/wp-stuff/uploads/sites/2/2014/06/100_6817.jpg
• http://lkrnac.net/wp-stuff/uploads/sites/2/2014/06/100_6817.jpg

EDIT3 – new fact

After usage of “Velvet Blues Update URLs” plugin that replaces domain for images, images are served from correct URL. So it looks like issue during image uploading.

never saw this hack before, but that is all it is – a hack. While it might work at some situations, wordpress core do not officially supports (yet) having two domains on one network install, and therefor YMMV to what will work and what not.
You are much safer having two different installs then taking this path.