I honestly don't know. I submitted for pre approval with London Embassy on 19 oct and received the pre and the approval itself 2 days ago. From what I've read they are approving by the traveling date order and I travel on 1st nov
I submitted mine on 19 oct and just pre approval yesterday and coe was approved a few hours after. I haven't seen anyone don't receive their coe before travel before but it can be very close like a day before you fly. It's nerve-wracking! Hope you get it soon :)
I understood now. It was silly of me to have such idea! I honestly didn't know this before otherwise I wouldn't have thought about it. Thank you so much for explaining π