I suspect you have the same issue as in FLEXIBLEAUTO ScalingTechnique, GetNoiseScaleDeg and decryption in CKKS - #4 by hilder Most likely 9 multiplications were done while the depth was set to 8. In FLEXIBLE* modes, the rescaling is done before next multiplication (which is explained in the cited topic). This is why the level is reported as 8 (because rescaling was not automatically done), but there is no more room left for computations.