The strike affected officers (masters and mates) on local ferries and domestic costal shipping. But the strike ended on May 28; well before the OP posted the original post. So no need for a warning now!

BTW: this was not a wildcat strike, but a legal, well advertised strike which is legal as a part of industrial negotiations. I'm surprised that the OP didn't get the opportunity to have the money refunded. Surely: bus substitution is acceptable for local travellers (which after all is the main business for the year-round service to Sognefjorden!), and also is according to the official terms of carriage. But when the boat trip as such is the main purpose of a package, ordinary customer protection rights in this country probably would indeed allow for a refund. Not necessarily from the quay agent directly, but from the original provider of the package. But as the OP accepted the substitute (i.e. accepted the bus-substitution), however reluctantly, no refund is due.