JJ Buffer Circuit Issue

[duutiphool]

Hey all, I am trying to simulate a buffer JJ circuit with the following netlist:

**JJ Buffer Circuit
**Igate <Ic2<Ic1
L1 n1 n2 0.125p
B01 n2 0 jmodel1
.model jmodel1 jj(rtype=1, vg=2.8mV, cap=0.007pF, r0=160m, rN=16m, icrit=2mA)
B02 n2 n3 jmodel2
.model jmodel2 jj(rtype=1, vg=2.8mV, cap=0.007pF, r0=160m, rN=16m, icrit=1.5mA)

L2 n3 n4 0.125p
Rout n1 0 2
Igate n3 0 0.02m
*VIN n1 0 pwl(0 0 300p 0 301p 827.13u 302p 0 600p 0 602.5p 827.13u 605p 0)
VIN n4 0 pwl(0 0 300p 0 302.5p 827.13u 305p 0 600p 0 602.5p 827.13u 605p 0)
.tran 0.01p 800p
.print DEVV VIN
.print DEVV Rout
.print PHASE B01
.print PHASE B02
.end

my incident pulse is at n4 and I am taking my output from ROUT. Ideally I should see near zero output on the voltage across ROUT but I get the attached figure. It seems like I am getting a negative and positive peak but in different time frames. (I am assuming I am messing something up they should be appearing at the same time). Most of the parameters I've used are trial and error selected for the forward incident i.e. Vin incident at n1 and output taken from ROUT but when I do the reverse I get the weird spikes. TIA

Here is the circuit (note that during a forward sweep, VIN is at n1 and Rout at n4 while trying to do the opposite, VIN will be at n4 and ROUT at n1)

Here is the input RSFQ train I am generating using PWL

During forward sweep i.e. VIN is at n1 and ROUT is at n4, the output at ROUT is close to VIN (as intended in a buffer)

Here is the phase across B01 and B02

Next I did a reverse pass, here is the Voltage across ROUT: (You will notice the negative voltage appearing after the positive spike)

Here is the phase across B01 and B02 during the reverse sweep: