Problem with setting initial voltages in LT Spice
If you look closely, there is an initial spike of whatever you imposed it to be, but then the voltage discharges quickly through D21-D23-D20-...-D1 to ground. The circuit is behaving normally, I'd say. BTW, you named the same node twice: Vout and Vc. In this case, LTspice will consider the last placed name.

Else, for any circuit involving initial conditions, you can try adding .tran 10m uic to complement the .ic card. Or delete the .ic card and set ic=... next to C1's value, like this: 2n ic=20k (btw, those F do nothing, unless they are the first letter, when it means femto -- avoid units). This should work without uic, too.