Conversely, a SAS-issued inbound ticket on AY (after last minute rebooking HEL-OSL) didn't work for me the other week - and even showing the original SK metal boarding pass didn't work.
That was, however, a tip I got from the purple shirted people - if the domestic boarding pass doesn't work at Connecting Norway, try the inbound international boarding pass.
There's nothing anywhere to suggest this is a trial anymore, for what it's worth. The only thing they appear to be trialling is exactly where the Connecting Norway corridor exits on the domestic side
.