Google is extending its warning for non secure sites – those served via http an not https.
From October 2017 any forms submitted via the latest version of the chrome browsers that use http will flag any fields as not secure.
It should look like the above images what the efect will be is as yet unkown many sites have over 30% or users using chrome and obvisly not all chrome users will update to the latest version.
The soulution is to switch to usig https for at least all your forms though it might be an idea to convert the entire site.