https://commons.wikimedia.beta.wmflabs.org/wiki/Special:Random/file - look for a file that has no captions currently, it will make life easier for testing purposes
- Scroll to the captions section, click "edit"
- Click "Add a caption" a number of times. I saw this bug with as few as five, but more will probably increase the wonkiness.
- Enter a language and text for each caption
- Click "publish changes"
Expected behavior: All captions are saved and the page is put into read-mode
Actual behavior: Some of the captions (three or four) are saved, some of the remaining captions are put into edit-mode, others are disabled (as if they were still being worked on). The "publish changes" button is re-enabled, but editing any of the enabled caption fields re-disables it. Deleting rows seems to work (for the enabled captions). Disabled captions' languages can still be changed in the interface, but it's unclear to me now if that causes them to actually be saved with the new language value.
Will test now on production to see if this happens there.