The reward for completing your assignment is that you were paid for the work you performed — not some imagined reciprocal arrangement where you are granted loyalty points for doing a good job.
That having been said, many a full-time position has grown from a freelance assignment, and you are smart to peruse and pursue opportunities at companies where you have worked.
Yes, you could send another email to this manager, but NO, you should not frame this like, “Why the change in attitude?”
In your email, refresh the manager’s memory about who you are, and say, “Sorry to be so persistent, but I’m interested in applying for a position in (name the department). I’m having trouble getting past the first round, and wonder if you have any ideas or suggestions that might help me to reach the right person.”
Dear Amy: I’m 52 years old and have come to the realization that I just don’t like my family.
We’re getting to the point at which we will have to visit with people, mostly family from both my and my husband’s side.
I don’t want to see anyone, and I feel childish about it, but I just don’t like these people, so how do I elegantly get out of going?
We’ve been able to use the “quarantining” response, but I think we’ll be in the green phase soon and all bets are off.