I was having the same symptoms. Long crank, battery was reading 12.7 v. The battery and alternator are both less than 3 years old. I had a track day recently where my TCS was very intrusive. When I got back to the paddock the yellow brake light, brake symbol and exclamation point were all on. I got under the car to take a look at the ground strap under the engine. It was completely green. It was NOT degrading in any way with slight twisting and inspection. It was very loose. I tightened it up with a 13mm wrench. The long crank was gone!. TCS acted normal. No more issues.
Fix: Try the extra ground test. If it starts fine or better check the ground strap.
