A short list of common bugs and issues:

SauceMan

High Priority:

• Dead Hard doesn't avoid damage sometimes. This is likely a network issue, where you may have used dead hard on your screen, but the killer never saw it before you were hit. The easy solution is to make Dead Hard client sided, so it's always reliable for survivors.
• Some killers (Spirit & Hag) can't be blinded in situations where blinding would work, such as kicking a pallet. Effectively making the perk lightborn built in to the character. The solution would be to slightly change their animations, and to make them look up a bit more.
• Huntress Hatchets. I don't think anything will be done about them since they've been an issue for so long, but the fact of the matter is the hitboxes for both the hatchets and survivors are too large, causing hatchets to hit objects and survivor it wasn't close to. It seems there's two reasons that cause this, one being that hatchets have collision that's larger than the hatchet itself. The second being that survivor's don't appear to have actual hitboxes, they seem to have one giant hitbox that surrounds the player, therefore meaning hatchets can't go in-between a survivor's legs, over the shoulder, under the arm, etc.
• Downed survivors sometimes don't make noise. There doesn't seem to be any specific reason, but survivors who have this bug are near impossible to find.

Medium Priority:

• Iron Maiden speeds up grabbing a survivor out of a locker. This was said to be fixed in 4.2.2, but has remained unchanged.
• Unhooking animation is very out of sync. Unhooked person starts too low, unhooker's animation plays too quickly causing it to be ahead.
• Sometimes in 2nd phase of hook you will randomly die despite spamming the struggle button quickly.

Low Priority:

• Some killers (Executioner & Blight) teleport slightly forward mid-hook animation, causing them to have their view clip into the survivor's legs for a second.
• Sometimes when clicking Play As Killer, the killer will be creepily staring at you right in your face.

It seems the overall conclusion is that BHVR just needs to test their own game.

Issues like the heartbeat being too quiet, killer actions not working, DS stun times, and unsynced hook animations should never have existed, because all of them come from extremely common actions that happen several times every game, so the fact they went unnoticed shows BHVR does not test before releasing.

It would only have taken one single 10 minute game to find several of these issues, but none were found before release.

BHVR should look into testing, as it will make the game more bug free.