Russia has always been playing dirty, and they are right now also pretty much in non-armed conflict with Finland too.
In just recent months, they have cut a gas pipe and data cable between Finland and Estonia, and right now they are shipping hundreds of illegal immigrants to the border, leaving their options to get shelter from Finland or go to the frontlines in Ukraine, knowing that as they don’t have required documents Finland cannot take them in. And Russia refuses to take these people back, leaving them with nowhere to go, which is a violation of the 1951 Geneve refugee convention.
The plan most likely is to stir chaos at the border and slip in Russia spies to a “russophobic country”