Considering the deadline was 2021, I'm not sure I'd characterize this as a recent change of heart.
Do you have any source for this? I'm having a tough time finding anything supporting your claim that Sweden has changed their position on this since brexit came into effect.
I can easily find bombastic claims from pro-brexit talking heads unilaterally asserting that the EU will continue to extend every privilege in a post brexit world, but I suspect it's possible they were not actually deriving those assurances from discussions with the governments which they claimed they were speaking on behalf of.