Process property empties on WF process

Hello,

I am working on a WF that poses a problem on process property level.

I have the process prop "Parent Outpout SiebelMessage Unitaire" in an output of a WF step. I have verify in log and it have a value :

"Output: @0*0*2*1*0*0*14*Return Message0*11*Return Code0*4*1*13*SiebelMessage0*9*MessageId0*11*Mes[...]"

But, in next step, I use it as input argument and it is empty in log.

I tried to modify the process prop, delete the step and pass the process prop as input argument on another step but it's the same result : the input argument is empty in log :

"Input: @00*0*1*0*0*0*0*13*SiebelMessage0