I don't disagree with any observations offered above. This hive was in swarm prep and missing a frame that should have been next to this frame, allowing the space. the picture composition shows is a bad angle, leaving a lot of questions. If this is the original position on the comb, they appear to have been removed and then set back on the comb.
I should say however, that the report and picture witnessed by two members of our Club that are known to me and trustworthy. One of them founded our Club and has kept bees for nearly 50 years.
I have seen one instance of two horizontal queen cells in my own hive. My horizontal queen cells shared a common wall, were perpendicular to the frame, anchored in one comb then crossing horizontally and terminating by contacting the adjacent comb, (cells were destroyed when the frames were separated during inspection).