It must be normal... because I am having the same issue. I assume it was some way to bake in less battery degredation?
I am comfortable running my EVs to 0% (albeit I charge right after)... but with this thing, I was almost stranded on the highway at around 7%. I thought it was literally...
Like I said. In my case, on two different turbos, there has been full regen since delivery new.
I previously had a Taycan that did withhold regen for about 800km. Definitely not on these turbos.
I have zero incentive to make this up.