Usual caveats that I'm not a diplomat, don't have all the facts, etc etc., but this doesn't seem like a rational move for Finland or NATO. The UK just yesterday agreed to protect Finland in the event of an attack, and the UK's involvement would likely bring in many other NATO powers anyway, so arguably they're getting protection they'd otherwise have to pay for for free. And actually, officially joining NATO will hav…
They are essentially stating that Russian gov. is aggressive enough to be a threat to them in the future but not agressive enough right now to create a "border dispute" to prevent NATO membership.
My take is that they should just have stayed out of the Russia US power game completely.