A response from another T owner:
however, I know the fluid is good per mech that performed it < 1 year ago
It is the PAS. First of all, if the PAS fails, there is a graceful degradation in support (eg. no power steering boost), but everything else will work, so no danger.
You can check one thing... On the sides of your intake
manifolds, towards the front of the car there are two small electro switches. They are literally bolted between the vacuum nipples and the throttle body. They have a vacuum line attached to them that connects to a vacuum line at the front of the manifold and two wires. These are the two switches that allow additional air into the manifold when the engine is idling and the powe steering is under pressure (eg. turning the wheel when you are at idle) so to prevent a stall. Mine make a tiny whine when they activate.
Secondly, if you follow the hydraulic line down from the reservoir there is a pressure switch, make sure this is also working properly. If it activates when it shouldn't it will activate the aforementioned electro switches.
Thirdly, make sure you have the proper type of PAS fluid. Look in your manual for the detail... It also needs to be changed fairly regularly (once a year) and does run warm - since it is hygroscopic and there is a vent at the top of the reservoir, it does saturate with water so it should be changed regularly. Make sure the vent stopper is there and not merely a hole to the atmospehere.
A whine can be further created if the actual PAS compressor is on a marginal wear of the seals, bearing or belt. If you need to change it, it is easy to remove from under the car or a bit harder to remove from the wheel well. But take it off, and bring the compressor to a standard auto shop to match it to an OEM one. Do not buy a Ferrari one as it will be a standard one in a yellow box and you will pay 5-7X the price of the PAS unit for the box.
As I said, mine has had a slight whine for over a year - no probs though.