Copying a page with a relative link from one wiki to another breaks the link

To reproduce:

• Create a page Main.Test.WebHome on the main wiki
• Create a page Main.Test2.WebHome on the main wiki, with a link to Main.Test.WebHome
• Create a subwiki (e.g. "test")
• Copy the Main.Test2.WebHome page to the "test" wiki

Expected:

The link should work and lead to the main wiki.

Actual:

The link is broken as it's relative and the Main.Test.WebHome page doesn't exist on the "test" wiki.