"Spot enemies at objectives using Recon gadgets"

They are not registering the right amount of enemies that i mark on objectives(I am using the Recon Drone). Ive marked like 4-5 people at a time on the objective and only counted as one. Even after i remain near to remarked them at the objective doesn't count them at all either. It's a pain in the butt to complete this Recon Specialist challenge.