If this is weird to Felix, it's only because, in all fairness, Dimitri has had about an extra year -- and his own complicated relationship with past Felix(es) -- to mull over their state of affairs, and while he can't say open communication has been their forte at any point, he can at least voice this much about his feelings without shame or overt reservations. No matter the time or place, or even whatever has come to pass between them, his one unquestionable truth is that Felix is his friend.

Which is why he can take the snappy response in stride, and even smile when Felix more or less accepts his offer, even if in his own way. Not that there is any reason to expect gratitude, to begin with; for all that Felix has done for him and the kingdom alike, this is barely repayment.

But, even that warm smile isn't enough to wash the mild surprise off his face when Felix claims to have already met Edelgard-- and the fact that they have run across each other isn't as strange as Felix's entire shift in demeanor. He would have expected him to act annoyed, or perhaps haughty, but this is... hmm.

"You have? In that case, I imagine she must have informed you about our truce, provided you gave her a chance."

In other words: you didn't pick a fight, did you? (Spoilers, he sort of did.)