...referring to for changing channels? If so, don't forget that rogue radio waves can cause all sorts of troubles. It's likely you are encountering just such a scenario where the extra telly is located.

What happens when you move the 3rd TV w/ Magic Eye to another location in the home?

Did you try using the anti-interference device listed on the following site:
http://www.aerialsat.com/search/tag/sky-magic-eye.html