article author on editing

Hi,

I´m using Gravity forms for my users to able to create blog posts.

Using StickyList I want administrator to be able to see and edit those blog posts from frontend.

It all is working good but one thing. Author is changing to administrator everytime I edit any post with administrator user.

Of course I´m using “set connected user as author” but I need this to be skipped on editing, leaving the original author…

Any ideas? perhaps some code to include in functions.php?

Thanks a million