Pretty certain this is a dupe. It's related to a logging issue.

Translate doesn't do anything here, it's core.
https://www.mediawiki.org/wiki/Manual:$wgUseAutomaticEditSummaries

I don't think so. MediaWiki is certainly responsible by the edit summary of the page being *created*, but are you sure it is using the [[MediaWiki:autosumm-new]] summary also for normal edits (i.e. when an *existing page* is edited)?

All metadata of edits on translation pages is carried over from the corresponding edits on Translations namespace, as it must. Yes, the unit is created when it's fist translated.

So it should use different metadata for these edits outside the Translations namespace, because this history doesn't makes sense:
https://www.mediawiki.org/w/index.php?title=Huggle/pt-br&action=history

(In reply to Helder from comment #5)

So it should use different metadata for these edits outside the Translations
namespace

No it should not in general, because bot/minor/whatever flags need to be respected; nor in particular, because otherwise users would have no way to alter edit summaries in translation pages. Wasn't it you asking for users to be able to attribute authors etc. in edit summary?

Yep. It was me. But I don't get it. There are two edits being made, only one of which is creating a page, so only one of them should say so in the summary (if there was no custom summary provided, when that is possible).