When a heading is followed by a custom tag with a linked heading in it, the link and linked text is removed on edit.

See the steps to reproduce for details. This is occurring on the rc5 release, as well as the previous svn version 3192 that i had checked out. I tested on two sites and was able to reproduce.

Steps to reproduce

In an otherwise empty ezoe block:
1. Create a header with some text (i.e. a heading 1)
2. Create a new line, and put a custom tag (factbox on it)
3. In the factbox create text, then link the text
4. Change the text in the factbox to a header (i.e. a heading 1)
5. Store the draft

The linked text in the factbox will be removed completely.