Funny, just went through this on my 2008 S this past week.
Yes, all four of your sensors are dying, or near end-of-life.
I priced the Porsche OEM replacements and discovered they cost $150 apiece. That's $600 for all four.
Purchased
these 3rd party sensors at half that cost, installed, reset the system, and now everything is happy.
Good luck!
dw