How old is your Pi? Do you know if male or female? My female WCP makes that noise when she is hormonal, and always signals us to distract her from what she's doing.
It sounds like she may be feeling hormonal. Is there a specific time she does it? Pisces always does it if she gets to the floor and under a cage so we try to keep that from happening,
In our household, it is known as the horny honk. It's a wheezy sort of noise that kind escalates to sounding like a chew toy. Jimmy can get pretty loud sometimes, but seems to cool off pretty quickly too.
If you pay attention to what is going on when your pi makes this noise, you can maybe adjust things so she can cool off a bit. For Jimmy, usually it's when she gets under a toy and has it rubbing her back. I just move the toy away from the side of the cage or higher off the perch.
Mine does the honk honk honk horny dance most days when she's particularly happy to see me. We move toys out of the way but mostly we just don't engage with her when she does it and she just does her thing (leaving the room sometimes stop her but then she goes back to it when we come back). She also makes what we call her duck sound which is a single sort of hoarse "quack". It usually means she doesn't like something or its a warning to a person if she doesn't like what they're doing. Its also known as level two (level one is a sort of trill that sounds like it could be positive but isn't. Level three is a full-on smoke detector)