In fact, the video from the summit in Salzburg shows that May stands in the crowd of her colleagues and shakes hands with them, and Merkel approaches this crowd. The British PM turns to Merkel for a moment, smiling. Then the Chancellor of Germany shakes hands with Lithuanian President Dalia Grybauskaite, who stands next to May. She also begins to shake hands with the rest of her colleagues, still with a smile on her face. As Merkel stands with her back to the camera, throughout the scene we do not see the expression on her face.

It is worth noting that on the videos published earlier that day, we see that May and Merkel enter the building of the summit together, talking between themselves. It is therefore not surprising that later they welcomed other colleagues - they had already greeted each other earlier.

Further debunk by The Insider.