Steps to reproduce:

1. Start with a page that contains this kind of formatting:

;Heading with [[a_long_link]]

2. Try to turn it into this:

'''Heading with [[a long link]]'''

Since HTML association lists aren't supported, to remove the formatting, I made a blank line above the "list", copied the text, and pasted it into the previous line. That gave me this:

Heading with [[a_long_link]]
;

Then I set the text bold (because the bold-face appearance was the purpose of (ab)using the association list), replaced the underscores with spaces, and backspaced over the last line, to remove the ; markup. It looked good, so I saved.

Results:

'''Heading with [[a_long_link]]'''

Expected results:

'''Heading with [[a long link]]'''

I can only reproduce the link problem if the [[long_link]] was originally in the "list".