I’ve seen this too when moving topics out of a category where solved was set, any way to fix this @sam?
When moving a topic out of a category with solutions, remove solved stuff
When moving a topic into a category with solution, make solved possible
Agree, we should get this cleaned up, for now pr-welcome
Added Trigger DiscourseEvent when topic category is changed by bekicot · Pull Request #4785 · discourse/discourse · GitHub, so that plugin can hook into :topic_category_changed. I think it is required in order to fix this issue.
Thanks for the PR @bekicot 
I was just curious but is it possible to avoid adding a DiscourseEvent trigger and just add a model callback which checks when the category_id has been changed?
Seems like this is still happening.
A topic marked as solution which is moved out of a category with solutions remains marked as solution (and cannot be unchecked as such)
When one of the replies is marked incorrectly as the correct answer, then the admin sees that the category is wrong and moves the topic to another category. The marked replay is still displayed as the correct answer, even if this feature is not enabled in the new category.
In these cases, the admin can not cancel the marked replay. It should change the category to where this feature is enabled. Cancel the correct answer and change the category again.
It would be a little easier if managers could cancel the correct answer in all categories (even those with this feature turned off).
对我来说，这看起来像是对 Carelessly splitting a solved post to a new topic breaks things 的修复。
它似乎没有修复 OP 中描述的问题，该问题是关于将整个主题移动到不允许启用解决方案的另一个分类中，而不是关于将一些帖子移动到另一个主题。当我移动 https://meta.discourse.org/t/personal-messages-username-search-filter-doesnt-work/371848（这是一个已解决的主题）到不允许解决方案的 Feature 分类时，解决方案不会被移除，也没有警告。
它解决了这个问题：
但我认为问题还有更多，所以我们可以保持这个开放。
嗯，我还是不明白。这不就是我刚才试过的吗？
标记为解决方案的主题
我选择了这个被标记为已解决的主题 `personal_messages:username` search filter doesn't work
它从一个有解决方案的分类中被移出
我把它移到了没有启用解决方案的 Feature 类别中
仍然被标记为已解决（并且无法取消勾选）
它仍然被标记为已解决。这次修复在流程中改变了什么？
抱歉，我现在明白你的意思了。我之前将此视为一个移出分类的标记为解决方案的帖子。
不过，我会将此项排队修复，因为我认为这应该对我们对已解决帖子所做的工作进行一次小的改进。
