Unable to recover and transition back to the SICK state after SICKER state

[shirotyan]

thank you very much for providing this package

I am trying to use this package to simulate the state of mental illness patients, and mental illness can recover to a stable state after relapse. However, when I use this model, the stable SICK state can replase to SICKER state, but SICKER state cannot recover back to SICK state .

hope to know how to handle this issue, thank you!