Problems with wyverns

[Arsoek]

I already posted this on reddit, but no luck so ill try again here.

Okay, so I was trying to get Souls of Flight for my wings, but no Wyverns were spawning. I was running around a platform for at least an hour and Harpies kept coming- loads of them-but no Wyverns.

After searching it up, I saw people on Reddit saying, "It's RNG, tough luck," etc., but one guy said, "They spawn during Blood Moons." After looking that up and finding nothing on it, I just assumed he was tweaking and went for another 30 minutes.

After still not having any spawn, it became a Blood Moon while I was on the floating island, and suddenly they started coming like crazy. I'm saying there was not a minute where there wasn't a Wyvern. I died multiple times, and every time I came back, there always was one.

During the Blood Moon, I killed one, but it didn't drop any souls. I just thought, "Huh, tough luck," but after I killed another one and it didn't drop any either, I looked up the chance of it dropping. To my surprise, it's a 100% chance of them dropping at least 10 souls.

So now I'm wondering, what the freak is going on? I checked where they died, I checked the floor, but no souls.

Were they not real Wyverns and some mutated Blood Moon Wyverns? Is my world cursed and will they not spawn normally?

 

[ppowersteef]

Assuming this is just a vanilla game.

Wyverns should spawn at the layer where Harpies can spawn, but they are more rare, and will not spawn if you're standing at a background wall, or if there's an NPC nearby.

Blood Moons increased spawn rate of all monsters, including wyverns.
There is no special wyvern breed, a wyvern is a wyvern.

Souls are floating items, they are dropped at the head, but they won't fall down like coins, so you'll need to find a way to reach them (if they were not offscreen), or defeat the wyvern while it is close.

Souls of Flight should always drop from a wyvern, so if Souls actually are not appearing at all from it's head, then something weird is going on.

 

[Arsoek]

For the first one, I thought maybe his head was off-screen and I couldn't get it, but the second one was nearly on the surface. So I don't get what happened