To Hitman WoA standards:
1. Bond was compromised, the enemy saw him and the compromise bar filled all the way. It was a front melee attack too and not a subdue so sound would travel both from the compromise and the melee attack. Would the sound travel that far to the other enemy? Not sure, depends on the difficulty and First Light's rules. But in OP's linked video, sound seems to not travel and cause panic when according to Hitman's rules it would, so either all the systems aren't in place, it's set to an easier difficulty, or First Light's rules are different for sound traveling. Gonna have to be a wait and see after release to see what's going on with that. Current indications are not good and immersion breaking for the video linked in the OP.
2. Guard 1 falls behind cover so wouldn't be seen by Guard 2 unless Guard 2 walks far enough to see him after the shown clip.
3. Unless I'm missing something Bond should have been compromised by the 2nd guard since he was in full view and no obstructions. Really weird that the first guard saw him but not the second. Even under the fastest of circumstances in Hitman, Bond was in the 2nd guard's FOV long enough to get the guard distracted and then investigate, followed by him finding Bond, and then since it looks like a Hostile zone and not just a Trespassing zone, the 2nd guard would then almost immediately start combat.
Really weird. The only other possibility I can think of is maybe that second guard wasn't given any sort of FOV yet. There were blind NPCs in Hitman in a few maps, maybe that guard was mistakenly given a blind tag or something. Isle of S'Gail for example had a woman playing a violin with a blindfold on near Janus' casket. There were a few others that I can't think of at the moment, but that one comes to mind immediately.