  We found an active state lasting for ~200 d in the AM CVn star NSV 1440 in
2022. During this state, the object reached a magnitude of 16.5, 2.0-2.5 mag
above quiescence, and showed a number of superposed normal outbursts. Such an
active state was probably brought either by an enhanced mass-transfer from the
secondary or increased quiescent viscosity of the accretion disk. These
possibilities are expected to be distinguished by an observation of the
interval to the next superoutburst. We also found that the brightness and the
course toward the end of the event were similar to the post-superoutburst
fading tail in 2021. The mechanism producing the 2022 active state and
post-superoutburst fading tails in AM CVn stars may be the same, and the
present finding is expected to clarify the nature of these still poorly
understood fading tails in AM CVn stars, and potentially of the corresponding
phenomenon in hydrogen-rich WZ Sge stars. We also note that the faint, long
"superoutbursts" in long-period AM CVn stars claimed in the past were not true
outbursts powered by disk instability, but were more likely phenomena similar
to the 2022 active state in NSV 1440.
