I haven't tested this "bug" carefully on S[OFU], but it happens on SE sites. If a question is converted to wiki because of too much editing, the subsequent answers are made wiki (as if the question were CWed by checking the box).
As I understand it, converting to wiki after some number of edits (by the owner) is done to discourage people from bumping their posts too much and to encourage them to make substantive edits. There is no reason to penalize people who answer the question of a compulsive editor.
- Though this behavior is annoying, it may not happen often enough for fixing it to be worthwhile.
- It's feature creep on an already abused feature. CW is already used more to prevent reputation gain than to make posts more editable. Adding a new type of CW question whose answers aren't automatically made CW may be asking for trouble.