I thought I had been testing your E builds but I guess I wasn't. I have version E2.01, E2.02, E2.1.1 on my system and they all have the same problem... 
never noticed... The most recent build that I have that works as expected is 993 (Yafaray 0.1.99-beta3 (2015-05-02) David Bluecame experimental exporter for Blender 2.74.5).
Maybe you changed the way this feature works when you went to the E builds. I may be missing some code you added at that time.
Edit: Here is a thread in the YafaRay forum about Transparent Refraction... Transparent Refraction
Thanks,
oort
never noticed... The most recent build that I have that works as expected is 993 (Yafaray 0.1.99-beta3 (2015-05-02) David Bluecame experimental exporter for Blender 2.74.5).Maybe you changed the way this feature works when you went to the E builds. I may be missing some code you added at that time.
Edit: Here is a thread in the YafaRay forum about Transparent Refraction... Transparent Refraction
Thanks,
oort