When a page is protected, a human-readable timestamp is written in at least two places: the protection log and the page's own edit summary.
The edit summary writes a timestamp in UTC, whereas the log shows it according to what the user chose in the preferences or according to the wiki's default local timezone.
The situation in the log is sensible, but showing the edit summary always in UTC is not great. It's fine for wikis in world languages, like English or Spanish, which don't have a defined wiki-wide local timezone, but for languages that are mostly spoken in a certain timezone it's inconvenient. It makes more sense to write the timestamp in the edit summary in the wiki's chosen local timezone.