Hello Utk2024
@Krist said it correctly (and I missed to say that im my response): the Berner Oberland Pass is not valid on EC / IC trains going through the Lötschberg base tunnel. It is only valid on the panorama route going via Kandersteg and Goppenstein.
See the validity map where as the route through the Lötschberg base tunnel line appears as a grey line = not valid.

BOP holders are subject to pay a surcharge of CHF 90 per person when using the EC / IC trains between Spiez and Visp.
Kind regards,
Roland