The measured effect is detected both in exposed cells and near, but separated, non-exposed cells. This "bystander" effect is shown to be mediated by biophotons emitted from the exposed cells.
Another experiment that shows bystander effect after exposure to radiofrequency radiation is available here  although they didn't do measures of biophotonic emissions.
 Zeni, O., Romeo, S., Sannino, A., Palumbo, R., & Scarfì, M. R. (2021). Evidence of bystander effect induced by radiofrequency radiation in a human neuroblastoma cell line. Environmental Research, 110935.
Last modified on 03-Mar-21