Two things, both about the difference between the machine an action happens on and the machine that decides what it means. A Trol's fists were being handed the boss bonus on the host's machine, where the hit does not belong to the local player. And every player's own config file was being read as truth, in a game where everyone has to agree on the numbers.
v1.4.19 taught the Fenrir's forms to walk on other people's screens and said plainly that the attacks would need their own fix. This is it — along with a Fenrir who turned back into a human at every sunrise regardless of what the tier allowed.
A tester brought a second Skadi along, turned into Moder, and found that each of them saw themselves correctly and the other one full-sized. That is the whole class of bug this release is about: a form built around the local player, with the remote copy left to guess.
Five tester reports, and four of them turn out to be the same shape of bug: something the mod computes for everyone except the player it belongs to. The Trol's height existed on every screen but their own. The Fenrir's forms animated for everyone but the transformed player's onlookers. A truced mob took a hit personally and forgot about it one frame later.
Valheim has exactly one flight, and it is the debug-fly flag the developers use to move around their own game. The Aswid's bat has always flown on it. What nobody had read closely is what vanilla does with that flag: it treats the player as not really present. Six methods act on it, and between them they meant a bat could not be seen, heard, woken for, or hurt.
That, a night-only restriction that had never once been enforced, and Skadi's spells finally paying into a skill.
One fix, and it's a multiplayer-only one: the peace every race is supposed to have with part of the world was silently failing for anyone who wasn't the client hosting the mob.
This build also swapped the Sverm's Yagluth form, which never made it into the changelog at the time — see the second half of this post.
Dragons get a sprint, a reverse gear and the ability to climb out of the sea. The Skeleton's progression finally does what its description has said all along. And three races stop being invisible to everyone but themselves.
Returning from a monster form stops replaying the animation you see when you join a world, remote dragons finally move and stay in the air, Trols are the right size for everyone else, and the Aswid keeps what it has eaten through death.
The seventh race arrives, races stop being console-only to manage, Skadi's costs move off eitr entirely, and the Aswid's Vampiric Aura stops quietly halving its own damage.
The dragon forms fly properly now. Skadi's flight was rebuilt from a free-camera noclip into real aimed flight, timed forms finally expire on their own, and a severe multiplayer bug that stacked thousands of dragon models on other players' clients is gone.