When I created a pdf form in Acrobat X and sent it to client, they filled and signed it with Reader. When I got it, it was blank. They used the Echosign option.
Can you find out exactly what version of Reader they used?
Ver 16.03.15 for iPad.
On Thursday, March 24, 2016, George_Johnson <firstname.lastname@example.org>
Retrieving data ...