  We report on follow-up observations of the Seyfert 1.9 galaxy IC 3599 with
the NASA Neil Gehrels Swift mission. The detection of a second X-ray outburst
in 2010 by Swift after the first discovery of a bright X-ray outburst in 1990
by ROSAT led to the suggestion of two very different explanations: The first
one assumed that IC 3599 exhibits outbursts due to repeated partial tidal
stripping of a star, predicting another outburst of IC 3599 in 2019/2020. The
second, alternative scenario assumed that the event observed in X-rays is due
to an accretion disk instability which would suggest a much longer period
between the large outbursts. Our continued monitoring campaign by Swift allowed
us to test the first scenario which predicted a repetition of high amplitude
flaring activity in 2019/2020. We do not find any evidence of dramatic flaring
activity with factors of 100 since the last X-ray outburst seen in 2010. These
observations support the accretion disk scenario. Further, while IC 3599
remains in low emission states, the long-term X-ray light curve of IC 3599
reveals ongoing strong variability of a factor of a few. The most remarkable
event is a mini flare of a factor of 10 in X-rays in December 2022. After that
flare, the otherwise supersoft X-ray spectrum shows an exceptional hardening,
reminiscent of a temporary corona formation.
