Nick Petit

The RBD Bullet Solver has an option in the output tab to export "age" and "active_age" as attributes. age is the time since the rbd piece first appeared in the sim, active_age is the time since the rbd was last activated - if you have pieces that become active, then inactive, then active again it will be reset every time it changes from inactive to active and 0 whenever the piece is inactive.
To get the active_age out of the sim, make sure you add it to the list of attributes in the output tab > transfer attributes.

From there, to get the activation frame, you can do:

Here's an example. When the columns move between the 2 posts, it deletes the outer constraints to let the pieces fly in all directions with an initial force applied to the pieces.
To do that it first needs to find the pieces attached to the constraints' anchor points as the constraints themselves don't actually move during the sim.
It uses 2 wrangles in a sop solver which allows you to access both the constraint geometry and the rbd pieces geo, one to delete the constraints - it needs access to the rbd pieces as mentioned above - and the other simply adds a random force attrib to the rbd pieces.

If you have an example hip you can share here or through support I can take a look. It's hard to tell what's going on without that unfortunately.