RedBull

I would check on leakages first, as when pressure got low on my Jaguar, I discovered a leakage and simply replaced a steering hose (https://www.carid.com/power-steering-hoses/), and everything went fine. If you do not discover anything by yourself, you may simply take your Jag to diagnostics, and they will tell you the exact reason for a couple of minutes, in order not to guess.

I believe that this could've happened due to one of these two reasons: 1. The steering fluid filter wasn't replaced in time (or you changed power steering fluid without cleaning the system with the same liquid) or 2. Quality of liquid you added/filled in was poor. If I were you, i would go and shop for aftermarket OE-quality pieces (https://www.carid.com/power-steering-hoses/), as from my experience I know, that they are no worse than ones by Jaguar, yet are way less expensive. This way I ordered a power steering cooler and a couple of hoses.

It looks like the filter and the while system is dirty. As whenever you change the steering liquid, it is a must to clean it first (you do that with the same steering liquid you are about to fill in). I faced the same case when had to replace the power steering cooler (https://www.carid.com/power-steering-coolers/). First, it was a problem for me to find one. Next, when we took the old one apart, we noticed that the fluid went black, though usually it was pink. The problem in my case was about a clogged filter, and then the whole system was dirty from inside.

I saw such Alpines on e-bay, brand-new ones. Check in car audio section.