While editing a page in Rich Text mode, the inclusion of an invalid link causes the "link" parameter to duplicate for each time it is saved. Subsequently, a "[]" will be displayed after at least twice saving the page.
For example, adding an invalid link in the page and saving the page numerous times results in:

"<alias>|^{<invalid link>|}<invalid link>|..." (depending on the number of times the page is saved)

to

"[ ]"