That was Method #1It will go back to auto mode after you've engaged the paddle. The problem you're having is that it's not happening quick enough for you.
So here is what you do to fix that. When you are approaching a corner, downshift with the left paddle and when you are ready for full auto again pull and hold the right paddle. You're now back to motoring in full auto mode!
It can still take a second or so to fully change back, but this is the easiest way to do it.
Side note... If you pull both paddles you'll go into neutral. Pull right paddle to re-engage.
I am sure you are aware that in about 6 sec after you downshifted it will revert to full AutoPDK...
Method #2 (not recommended to use in the twisties, until you are thoroughly familiar with the PDK behavior).
Instead of using the left paddle to downshift, you punch the gas pedal.
Here comes the hard part:
Depending on how 'deep' the punch was, and how short in time, one of the following will happen:
1) Too shallow and short punch (you have to figure out what this means): The car will accelerate, possibly anemically, since it is in low revs for the downshift.
2) Just the right depth and duration punch: The car will downshift one gear and stay in automatic.
3) Sublimely correct punch: The car will downshift two gears and you wanted to downshift two gears, and stay in automatic
4) Floor and hold the gas pedal: All **** breaks loose, the car will downshift as many gears as it can, taking the engine to or near the red line , you suddenly have to deal with close to 300 screaming horses and the upcoming turn (that's why you wanted to downshift, right?), the fauna around you will be distressed, and if you don't deal successfully with the horses and courses above, the flora will be distressed too (...if you get my drift... )