Why Nanatsu no Taizai members didnt recognize each other at first in season #1? I'm rewatching Nanatsu no Taizai, and many of the members (Meliodas, Ban, King, Gowther, Diane, Escanor) didn’t recognize each other at first, or they weren’t sure about the others really being who they were. Some examples,

Ban after re-meeting King: And you, who you are?


Diane after meeting Meliodas: Are you a holy knight?


Escanor after meeting Ban: haven’t I seen you before?


Gowther after meeting Meliodas and Ban: yes, I really am Gowther.
Those traits, that posture, that scar, as I thought, you are undead
Ban. That means the young guy whose appearance is similar to Meliodas
is..
Meliodas: that's right, I'm Meliodas.
Gowther: what a surprise.
Ban: and what do you think of him. I bet you'll be surprised more he's
King.
Gowther: No, he is another person

Why did this happen? Supposedly people like Meliodas and Ban didn’t change their appearances and they only separated 10 years ago.
For Meliodas and Ban, I am pretty sure they did recognize each other. It's just the surprise they get after 10 years.
For King and Ban, King did recognize Ban, and Ban to King. King's hate of Ban for Elaine's death was the reason why he acted like that. Ban just doesn't care.
For Gowther, the others have not really seen him in the flesh before that moment, he has only seen King in his old fart form, and he did recognize Ban and Meliodas.
Do point out any episodes that prove otherwise. It can help move the discussion going.