The reverse engineering return rate is not currently working as intended. In an upcoming patch, we are improving the reverse engineering rates – especially for the higher-level items. We are also looking into the issue where a player receives “You already know that schematic” instead of learning a new research variation.
Patrick Malott
Systems Designer
In diplomatic language, this probably means "Oh my God, we screwed up".
I have been RE-ing 53 (FIFTY-THREE) Blue Steadfast 22 enhancements and didn't get a purple.
And I'm testing on others, looks the same.