Steps to Reproduce:

1. Create a translation that is considered not fully translated (my case: https://pl.wikipedia.org/wiki/Special:ContentTranslation?title=Special:ContentTranslation&campaign=contributionsmenu&to=pl&page=Gri%C4%8D+Tunnel+%28Zagreb%29&from=en&targettitle=Wikipedysta%3ABonvol%2FTunel+Gri%C4%8D)
2. Click Publish (top right corner, a pop-up warning window appears that there are sections not yet translated. Note: before I selected an option to publish in the sandbox
3. When I see pop-up, I decide not to publish the content, even in the sandbox. However, I do not click the rejection button, just pressEsc on the keyboard (browser: Firefox).
4. The content gets published anyway (https://pl.wikipedia.org/wiki/Wikipedysta:Bonvol/Tunel_Gri%C4%8D)

Actual Results:

Expected Results: