Testing in 2017.2.0.26349
The triggered rule should run in initialization.
A similar rule, pulling down the Org Unit from Employee.
This is the first field, validated with the Display Name used as the default value as this is what the picklist is expecting. This wouldn't work if the picklist was using loginid.
OrgUnit is exposed as an additional field.
Testing that shows the values to be populated when I first open the SR.
Updating the value also triggers the secondary rule.
The picklist was using the loginId and since it worked on update i didn't even consider changing it. Thank You!