Datacenter .. 8.20.x
Parent Issue – Issue Type -- Informat
Below is Subtask Workflow

Sub-task : Workflow :
There is custom field, “Infra” in the subtask.
- When status is in “REBA” the custom field “Infra” should be Read and Write (Also if and if the parent issue type is “Informat”
- When status is in “In Progress” the custom field “Infra” should be Read Only (Also if and if the parent issue type is “Informat”