Animation errors
We've spotted some goofs in the animation of the anime.
Kana without halo
This is Kana in her own Clock Tower, looking down on Rakka in episode 4 (07:57). Here her halo disappeared, most likely because the animators forgot to draw it.
It was spottedOHBB by yatpay in the HR Bloopers threadOHBB.
Four-eyed Fangirl
Rakka is bothered by the fangirl in the thrift shop in episode 8. When Rakka runs away, the fangirl steps back, and her eyes double (11:24). This can only be seen by watching the scene in slow motion.
DHC, Inc. spotted it in this ThreadOHBB in Sep 2004. A very funny discussion followed.
Notice that few frame before, the Haibane Fangirl blinks, but her face doesn't change. It means that her eyes were on separate drawings (so that the whole body doesn't have to be redrawn every time). But few frames later, she backs off as Rakka runs away from her. As Fangirl reacts, her whole body is redrawn in a different pose, including her eyes. Whoever composited the scene, forgot to "turn off" the column where her "floating" eyes were, and forgot to "preview" the scene before exporting it to the final editing...
Shrinking Washi
murphy attempted to measure the heights of the Haibane in the show, but after some discussionOHBB it seems that the drawing is not always exact. For example, in episode 10 Washi is the same size as Kuramori, but in episode 3 he seems to be much taller than Rakka and Hikari. (In the world of FHD Remix, they are different individuals and their similarity in voice and appearance is plausible.)
Changing studio door
The door to Reki's studio looks different throughout the show. At least 2 different designs were spotted. It even changes within the same scene. See the threadOHBB.
In addition to the doorknobs constantly changing, the studio door's direction of opening changes when Rakka enters the room for the last time, to save Reki. This was spotted by Belthazar in his "Thoughts and Questions" threadOHBB in Dec 2003.