I have a problem with my integrated analog switches.
I am using the PMOS configuration attached.

The behavior that i want to have is: at first the output voltage should go down from 0V to -60V, afterwards it should go up from -60V to +180V.

What my circuit does in reality is:
It starts from -50V and goes down to -110V, afterwards it goes up from -110V to +120V.

So, the problem is that it doesn´t start from zero, but from -50V instead. What can be the reason?

I already tried to decrease the on resistance of transistors through increasing the transistor size, but this makes the functionality even worse.

Can it be a problem of leakage, big Cds or charge injection?
Does anyone have a simple solution?