On two occasions I have placed plastic explosive on the ground in a building but cannot arm it with a remote detonator.
The prompt to 'arm' the explosive will appear, the action will complete but the explosive does not arm. The explosive and detonator do not combine.
Also, the plastic explosive placed on the ground in the building does not appear in loot 'vicinity' and I am unable to pick it back up. The plastic explosive is now useless and stuck on the floor.
This has happened in the barn style building, with the boxes/hay stacks and wooden steps/floors, as well as the hospital building found in Pavlovo military.