Solved, if you got the same problem, its because the MSAA, if changed to TemporalAA or FXAA you get the same as the deferred render, but if you, like me want to use MSAA, just add a Multiply (I used by 10) in the Opacity Mask, like the image below 
material
191026-
Result: Forward Render + MSAA
191027-
Thanks to DanielW, from his reply at this post