Yeah, it's also possible that it was the Swedish armed forces/NATO doing the jamming as part of the exercise. In this case they would probably jam both GPS and GLONASS.

Seems politically quite risky though, what if some ambulance didn't reach their target or something like that? (Although I guess an easy workaround for that could have been tight coordination with the local rescue services - stop the jamming the moment there's an ambulance/fire emergency in the local area.)