The only it makes sense to me is that she didn't have any negative feelings and he let his guard down as he is back home?
I saw a comment on bato saying that in the light novel he did notice she was listening in on but chose not to reveal it to the grandpa (since he thought Tessia should know)
Ohhhh ok, that's more realistic and interesting, why didn't they includade that tho? Makes no sense
Art is most certainly NOT op.
i thought arthur was op, and u mean to tell me he couldnt sense or hear tessia behind that door