Bug enabled extended features

[joeauthor]

I am using Foxit PhantomPDF to modify an existing PDF that had enabled extended features. I do not need my users to be able to save forms. How do i remove/turn-off the extended features in Foxit?

Error message received in Adobe Reader:
This document enabled extended features in Adobe Reader. The document has been changed since it was created and use of extended features is no longer available. Please contact the author for the original version of this document.

[richell_huang]

Could you please help to send us a copy of the mentioned PDF form file ,so that we can better advise.If it is inconvenient to upload it here,please send us it to [email protected]

[swvermeulen]

I get the same error with pdf forms that are saved with foxit reader.
what I do:

I have a PDF form (made in LC ES2) with extended features enabled because we want the forms to be saved.
If the user uses Adobe reader from the start there's no problem.
does the user use foxit reader and saves the file, after that if you open it in adobe reader it gives the error: extended features is no longer available
adn the you are unable to change it.