WA GBBR - Fire Control Group Funky Function

[The Journeyman]

Parts I'm using:

• Iron Airsoft AAC 300 MPW lower
• ViperTech Hammer Assembly
• ViperTech Trigger Assembly
• Battle Arms BAD-CASS-3P (RS)

This peculiar function happens only in SAFE.
SEMI and FULL AUTO seem to work fine (e.g. hammer release and trigger reset works OK in SEMI, disconnector stays down in FULL AUTO until trigger release).

1st step - SEMI
I cock the hammer back and it is captured properly as advertised.

2nd step - SAFE
I press the trigger and it moves almost all the way just a hair before hammer release but hammer stays down (as it should).
An audible *CLICK* is heard when I press the trigger, almost like it captures the hammer on another notch, and the trigger stays in pressed position even if I release finger pressure.

3rd step - SEMI or FULL AUTO
As most of the trigger distance was already covered from the previous step, now I just touch the trigger and the hammer is released.
The amount of force needed is VERY little and that makes me uneasy as I feel like the hammer might drop with the slightest bump (which I found out that WILL happen after test bumping it)...

Has anyone else experienced this?
Any ideas what might be the problem and what remedy would be appropriate?
I wouldn't worry if the trigger would return to initial position while on SAFE since that would mean longer travel (and safer function) on SEMI/FULL AUTO.