How can I be terminated for something I was given permission to do?

I'm a 35+ year Delta Airline Flight Attendant. I was handed a watch while a customer was deplaning on October 14, 2019. I was given permission by a Delta Security official to leave the watch in police custody in hopes the owner would be found. 13 months later, that same Delta Security officer now states I did not have permission and went against his directive to hand over the watch on October 21, 2019. If I had gone against his directive to hand over the watch on October 21, 2019, why did it take 13 months to terminate me. I've been working the entire 13 months. I was terminated on December 17, 2020.