The fast rerolling algorithm doesn't take into account age and possibly other constraints from the scenario

[VotiveEcho]

Steps to Reproduce:

1. Create a custom scenario with a defined allowed age range.
2. Select the scenario.
3. Select the fast rerolling algorithm.
4. Randomize the pawn.

after some rolls you should find some pawns that are outside of the allowed age range from the scenario.

[Cellhawk]

This also affects Unnatural Regeneration for ghouls in Anomaly starting scenario.