Bullets solver, setting or changing attributes

Bullet solver is a bit strange in Houdini. It might not update values as you expect. Eg, you're trying to change the @active value using a sop-solver.
One solution is to use the Bullet mode in the RBD Solver. This usually works..But it might be slower? I think it has a multi solver built into it..

Another way to make it work is by utilising a multi solver and the Geometry Wrangle. This will let you access the SOP level stuff (there is an input tab you can mess around with)

So, your input RBD goes into the first input of the multi solver, then your Bullet Solver and any Geo Wrangles go into the purple input of the multi solver..