Has anyone experienced a situation where a pre-op diagnosis for fainting (syncope) was proven wrong during treatment in Korea? What happened and how was it handled?

Has anyone here gone through a situation in Korea where doctors initially diagnosed fainting (syncope) before surgery, but that diagnosis turned out to be incorrect during treatment? What did the medical team discover instead, and how did they handle the change in diagnosis? Did it affect the treatment plan, your safety, or the final outcome?