Incorrect results with calibrations in sub-budgets

Here is a test case involving calibrations and sub-budgets:

from gwinc import nb
from numpy import ones_like

class C1(nb.Calibration):
    def calc(self):
        return 900*ones_like(self.freq)

class C2(nb.Calibration):
    def calc(self):
        return ones_like(self.freq)

class N1(nb.Noise):
    def calc(self):
        return ones_like(self.freq)

class N2(nb.Noise):
    def calc(self):
        return 4*ones_like(self.freq)

class SB(nb.Budget):
    noises = [(N1, C1), N2]

class B(nb.Budget):
    noises = [ SB, ]
    calibrations = [ C2, ]

Save as B/__init__.py, run as python3 -m gwinc B SB.

Expected result: noises N1 and N2 both have magnitudes near 1/rtHz. But N1 is calibrated with C1 which applies a large multiplicative factor, so it should dwarf N2 in the sub-budget plot.

Actual result: apparently C1 is applied to both N1 and N2?

However, you do get a correct result if you comment out the calibration C2 in the parent budget.