FlyerTalk Evangelist
Join Date: Nov 2018
Location: Istanbul, Turkey
Programs: TK Elite Plus,BAEC GGL,ITA Executive, AFKL Gold,QR Gold,HH Diamond,Bonvoy Gold,ALL Gold
Posts: 14,186
This is because TK 800 is a triangle route. That's why most seats are blocked until OLCI or airport check-in.
They don't want an IST-BOG-PTY and a BOG-PTY-IST passenger to choose the same seats for the same flights.