Patriot ECS requires line of sight to a target

[Blackfyre]

In order to work, Patriot site's ECS must have line of sight to a target, which, I guess, is wrong. It is the only manned vehicle in a site, why would it require to be exposed? 

It used to work fine without line of sight, but then it has been changed without a mention in patch notes, so assume it is a bug.

P.S. I would imagine it must be somehow connected to radars and launchers, but it isn't the case in DCS, which is fine because it helps to offset AI stupidity (smart AI is very hard).

ECS-LoS-Patriot-engages.trk ECS-no-LoS-Patriot-does-not-engage.trk