List of steps to reproduce:

• Mark Abc for translation. This creates Abc/en.
• Remove Abc from translation system.
• Edit Abc, add “something” to the top.
• From anywhere, add {{subst:Abc}} and view changes or save.

What happens?:
Abc/en is substituted instead of Abc.

What should have happened instead?:
Abc should be substituted: you should see “something” you had added.