Valentino and K on a Misha May play date

This is the second playtime for Valentino, adopted through Misha May, and K, in training with Misha May. They are both nice neutered male dogs. I had every reason to believe they would play well together. They played for the first time on the day before, and had previously met daily while alternating being crated and receiving treats in each other's presence. Valentino has only been with dogs that are nice and has never been in a fight or even threatened. He has lived in the same home since he was 2 days old, first with his rescued mom and littermates, then adopted by his foster mom. K, under a year, lived on his own in Afghanistan until just 2 months ago. I imagine he met all kinds of dogs and experienced many situations that required him to ascertain whether he could trust and let down his guard or not. Both dogs are being respectful and inviting while exploring what will be and what will not be tolerated. I believe that as their play continues and they get to know each other better, their styles will become even more similar and harmonious