Direct report recruitment when on secondment

I have been on a secondment for over a year and due to go back to my home role in 3 months. I do like my home role so not unhappy to go back as the secondment has just been a project associated with the home role.

A permanent role has come up that direct reports to my home role. I wasn't told it was about to be advertised and found out when people started asking me about the advertisement. I asked the manager in my home role if I could see the applicants when they come through and they reluctantly agreed. I have had a couple of outstanding candidates reach out to discuss the role. The person currently doing the role is also on secondment and is ok but just ok.

I told my home manager about the candidates reaching out and their reaction was to turn their nose up and argue why they thought they wouldn't work out, none which were strong reasons at all. Then tried to say how the person currently doing it has been doing a good job. It's becoming apparent they are wanting to make them permanent even though they reluctantly advised they would have to interview the other candidates.

I need a sanity check, would you be annoyed you weren't told about the role going up? That you had to ask to be part of the process? How do I try and ensure they at least look at the recruitment fairly?