GHSA-4RMQ-MC2C-R495 Babylon Incorrect FP inactive accounting in costaking creates “phantom stake” that earns rewards after BTC unbond

Summary A state consistency bug in x/costaking can leave a BTC delegator with non-zero ActiveSatoshis Phatom Stake even after they have fully unbonded their BTC delegation, if their Finality Provider FP drops out of the active set in the exact same babylon block height. This creates a “phantom...