Steps to reproduce:
0. Find a message via Special:SearchTranslations that its next message is not for translation (but itself is enabled for translaton)
- Try make a change on that message
- It won't work
Sometimes the edit translation link just work as a hyperlink and would open the related message page. On that case you can middle click on the edit translation or open the previous editable message.
It reproduces on https://translatewiki.net/wiki/Special:SearchTranslations?query=%D9%84%D8%B7%D9%81%D8%A7&language=fa (click on third message edit, skip to next, edit the message, try to save the message, it won't work currently because next message is disabled for editing) but don't expect this link would work after a while because perhaps we would edit the messages listed after a while.