FDF no longer works in Reader 10.1.1. Worked in 9.x and previous

I have a web app that was developed many years ago to serve PDF "templates" with user data inserted into it's forms via FDF. Up until Adobe Reader 10.1.1 (currently testing with this version, possibly affects earlier versions of 10 too...), it stopped working in many browsers. I just tried with Reader v9.4.0 and it works fine as expected.

Here's a sample of some test from the app:

serve_pdf.cfm

<cfcontent type="APPLICATION/vnd.fdf">

%FDF-1.2

1 0 obj <<

/FDF <<

/Fields

[

<</T(field1)/V(hello)>>

]

/F(https://www.thesite.com/the_document.pdf)

>>

>>

endobj

trailer

<</Root 1 0 R>>

%%EOF--->

Did the FDF syntax change in 10.1? Can someone help me out please?

Thanks,

Dan