Recently, unsure which update exactly it started. But everything I do spawns virals, even during the daytime. I kill biters? Virals spawn, Looting chests and stuff? Virals spawn. Is this a bug? 
#Virals Spawning constantly
solar solar
dark ferry
It's not a bug probably, just these random activities usually spawns viral ok the area. This was and still a feature from a past update