  The addition of tunable couplers to superconducting quantum architectures
offers significant advantages for scaling compared to fixed coupling
approaches. In principle, tunable couplers allow for exact cancellation of
qubit-qubit coupling through the interference of two parallel coupling pathways
between qubits. However, stray microwave couplings can introduce additional
pathways which complicate the interference effect. Here we investigate the
primary spectator induced errors of the bus below qubit (BBQ) architecture in a
six qubit device. We identify the key design parameters which inhibit ideal
cancellation and demonstrate that dynamic cancellation pulses can further
mitigate spectator errors.
