Syntax for the calculated fields is different from syntax elsewhere. For
example to get the task name or planned completion date to the issue
custom form, this would be: Source Task.NameorSource Task.Planned
Completion Date To get the answer to a task custom field called
"customVar" to the request, it would be: Source Task.customVar Keep in
mind, it has to look exactly like the field name, so if your field name
is Custom Var, it would be: Source Task.Custom Var