I'm an 'expert' in OSL luggage. All SK staff was wrong (not surprising given that it's SK...), proving that SK is indeed a bunch of idiots. They should know better. They should also know that OSL isn't a 'nice, tiny, cozy airport', as it's a construction site (so much for cozy) and handles over 23 million pax per year (so much for tiny). It's extremely efficient, though, which makes it nice.

Here's the luggage policy for flying via OSL (given that your luggage is checked through to your final destination):

connecting domestic - domestic: your luggage will be transferred automatically
connecting international - international: your luggage will be transferred automatically
connecting domestic - international: your luggage will be transferred automatically
connecting international - domestic: you need to pick up your bag and deliver it at the bag drop (do custom's clearance yourself)

https://avinor.no/en/airport/oslo-ai...trip/transfer/

ps. I assume you didn't just run to the gate but had to go via the transfer area near gate 42?