since this type of interference is geographically relevant, it clearly has nothing to do with the war.
So, I'm not sure what the rationale is -- it might be worrying about long-range drones, like those light aircraft, flying around Belarus, but I've definitely seen some sources say that they believe that the Kaliningrad jamming is a function of the war.
This article, from late May, has the Finnish government saying that they believe that it's related to the war.
Jamming GPS signals over the Baltic Sea is “most likely” a side effect of Russia's anti-drone activities, Traficom, the Finnish Transport and Communications Agency, said today.
“The interference intensified when Ukraine's drone attacks on Russia's energy infrastructure began in January 2024,” Traficom said in a press release.
Estonia also blames Russia for the signal jamming, but the Finnish agency doesn't agree with the Tallinn government in defining the interference as a hybrid attack.
“It is possible that the interference observed in aviation currently are most likely a side effect of Russia's self-protection” that is used “to prevent the navigation and control of drones controlled by GNSS [Global Navigation Satellite System] or mobile frequencies,” Traficom said.