Wyvern Swoop Damage Bug

[Gardner Denver]

[HP=355]:sw <-- notice 355 hps going into the room

You hear movement to the southwest.
You hear movement to the southwest.
Darkwood Forest, Lair
Also here: wyvern, wyvern.
Obvious exits: south, northeast, northwest, southwest
The room is dimly lit
The wyvern swoops down and grips you in its claws!
The The wyvern lifts you high into the air, then drops you!
You fall to the ground with a thud, taking 0 damage!
The wyvern swoops down at you!
[HP=338]: <--- yet I lost almost 20 hps, I was not poisoned, and did not take any other hits

[DeathCow]

[HP=355]:sw <-- notice 355 hps going into the room

You hear movement to the southwest.
You hear movement to the southwest.
Darkwood Forest, Lair
Also here: wyvern, wyvern.
Obvious exits: south, northeast, northwest, southwest
The room is dimly lit
The wyvern swoops down and grips you in its claws!
The The wyvern lifts you high into the air, then drops you!
You fall to the ground with a thud, taking 0 damage!
The wyvern swoops down at you!
[HP=338]: <--- yet I lost almost 20 hps, I was not poisoned, and did not take any other hits

I'm actually fairly certain this is a content error on metro's part, I think that message is built wrong.  (I THINK I remember that)

[Gardner Denver]

Well something is up with it for sure.  I'm consistantly taking more damage that it shows in the message.  It looks like I'm taking roughly 17 more damage than the message is reporting.  Which would be about what my DR is on my AC.  I'm at /16.something DR.

It's like the message accounts for my DR but the actual damage done does not.