No, none of my callers reported a delay… Sorry I can’t help you with that.
But by the way, I have had problems since I have my S7 with /e/ (2,5 years) : callers get an echo of their own voice when I activate the speaker, so I can’t use the speaker 
I should search and post about it!
Edit: this is in fact a general S7 problem: Galaxy S7 echo during calls with speaker