One side of hammer not opening

[Rodan]

Anyone know the causes for one side of the hammer not to open up its on the same side where my power head is so maybe that is why but I would like to hear other peoples thoughts.

 

[Aiden22!]

Usually not an issue as euphyllia periodically close up and reopen. Could have been some food that got caught in the head, an attempt at splitting, or as u mentioned the powerhead causing some disturbance. Color looks good and the rest of the heads look great so I would say keep watching it and if it will ease your mind, move it to a less flow area.