Hi Satish,
Thanks for your inputs. My apology I should have clarified my requirements further. What I notice is that the Lead to Opportunity Sales Process business process flow is required (i.e. it needs to be visible on the form) in order for the system to capture the value for parent contact of the lead, when converting the lead into an existing contact.
If I deactivate the business process flow, or remove the Read permission from the user's security role so that it's not visible on the form, then when converting the lead into an existing contact, the parent contact of the lead becomes blank as the system seems to have lost that connection value.
And in my client requirement, I need to use the parent contact of the lead value in a workflow in order to populate the contact lookup for a child entity creation when converting the lead into an existing contact.
It's interesting why the business process flow needs to be visible on the form in order for that parent contact of the lead value to be captured, but that's the behaviour I have noticed in my testing.
In case I might have missed anything, please let me know.
Thank you!