Destroyer positioning of the ship or/and the (moving) modules, including the engines on top of the ship, can sometimes block sensors and prevent you from spotting any ship at all.
This can happen with other regular ships as well, not just on Destroyers. Bottom video, timer: 0:02-0:03.
What should have happened?
Sensors or radar should not get blocked under any circumstances, such as positioning, moving and rotating Destroyer modules, or just by facing engine section towards the enemy.
Possible affected objects or modules:
Destroyer modules that require constant tracking/locking
Repair Drones (will stop repairing or will just be visible but will not repair damaged hull)
Looting (collecting a container might suddenly stop or fail)
As you can see, this can happen on other ships as well, not just Destroyers. For a split second, the Guard lost the sight of a Destroyer. Check the timer: 0:02-0:03.
[2018.04.21 16.58.07.zip](< base_url >/applications/core/interface/file/attachment.php?id=16734)
[2018.04.22 23.47.20.zip](< base_url >/applications/core/interface/file/attachment.php?id=16744)