Please correct me if I am wrong but not all Xenia are pulsing....
Xenia species often referred in the hobby just as Xenia or with a preceding descriptive term for each general variety (ie Pulsating, Clumping).
In some Xenia sp. the corals pulse opening and closing the polyps rhythmically. The pulsing is more pronounced in lower water flows and often is quite exited after adding food or additives to the aquarium.
I would have to say you have a non-pulsing xenia on your hands there. If inncorrect I look forward to being corrected.
B.S.