Requested by is displayed instead of Number under catalog task
1) Navigate to sys_dictionary
2) Filter the list:
Column Name: requested_for
3) Open the Dictionary Attribute Record.
4) Open Dictionary Override for Opened By on sc_task table:
You will see "Override display value" is set to "True" and "Display Name" is "opened_by", which is the reason why "Opened By" is seen in place of Task Number.