Hey there!
I've just came around for the first time on my Sneak/Sniper character to play on the latest 1.4 patch but I've noticed almost right from the start the sneaking was being silly. I've tested it further but my conclusion stays. I've changed difficulty settings and everything but nonetheless a simple Raider immediately found me from about a 20ft away? I dunno. I came accross this at first in the settlement of Outpost Ziganya or something (it has a raider with a turret just down the hill but nonetheless about a 20-30ft away), before I even fired a shot or anything while sneaking I climbed the rocks to line up a perfect headshot but while I was aiming (still sneaking) he somehow spotted me and started attacking right off the bat. I dunno if they gotten this Sight Mama Murphy is so fond of or the Sole Survivor gotten clumsily during his break of a day but seeing how all but the last tier of Sneak is unlocked I still don't think this should be happening. And this has happened not only then and there, happened everywhere. Before I even knew of their presence they somehow seemed to know me. Unless perhaps Maccready is double crossing me which will result later in a swift bullet to his hat under the guise of a stray bullet in the next Super Mutant/Raider/Gunner attack. I'd like to know if this was a ninja fix of an maybe quite powerful perk or if this bug just snuck in during the parade (puns semi intended). If it's a bug, now you know it exists! If it's no bug, now I know it exists! Hope the community can shed some light in this darkness my nightvision scope can't seem to pierce.