Custom Fields (and I18N)

[Nobody]

I edited page and saved changes. GS changes pubDate and creDate. Why?
GS 3.1
CustomFields 1.8.1

Only windows systems store file creation and edit date. Linux systems store file's last access date, and file's last edit time.

I talk about fields in page file (XML <pubDate></pubDate> and <creDate></creDate>).
From info about Custom Field plugin: "The plugin automatically maintains a field creDate containing the creation date of the page, as GetSimple is sadly missing this."
<creDate> field contains date of first save of the page (date of creation).
<pubDate> field contains date of last save of the page.
But when I edit and save page, date of this save is stored in field <pubDate> (that's ok) and <creDate> (it's not correct behavior).
My question: it's error in plugin or it's some kind of my error.