Initial value assignment to task container element disappears!!

[NAGPAL,RITU (HP-Roseville,ex1)]

Hi,
 
We are in the process of upgrading from 4.5B to 4.6C. In the 4.6C
development system, I made an initial value assignment to WI_GROUP_ID
element in several tasks. The assignment was there for a few days and then
disappeared a few days back. So, if I go to the task definition (thru
transaction PFTC), the initial value assignment is no longer there for any
of the tasks.
I checked workitems of these tasks to see when it disappeared and it seems
like it disappeared for one of the tasks after I transported the task to the
test system. Don't know if there was any link between the 2....Can't tell
when it disappeared for all the other tasks as workitems were not created
for these tasks after the transport.
Has anyone encountered this problem? I did not find anything in OSS....Any
help would be greatly appreciated.
 
Thanks,
Ritu
Hewlett Packard