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).
We have addressed this by ensuring that if a solution post is moved out of the topic, the topic returns to unsolved state.
The user that is moving the solution post is notified of the impact before they complete the move action:
To me, that looks like a fix for Carelessly splitting a solved post to a new topic breaks things
It doesn’t seem to fix the problem described in the OP which talks about a whole topic being moved to another category where solutions aren’t enabled, not about moving a few posts to another topic. When I move `personal_messages:username` search filter doesn't work, which is a solved topic, to Feature where solutions are not allowed, the solution isn’t removed, and there is no warning.
It addresses this problem:
But I can see there is more to the problem so we can keep this open.
Hmm, I still don’t understand. Isn’t that what I just tried?
A topic marked as solution
I chose this topic that was marked as solved `personal_messages:username` search filter doesn't work
which is moved out of a category with solutions
I moved it to Feature where solutions are not enabled
remains marked as solution (and cannot be unchecked as such)
And it was still marked as solved. What did the fix change in this process?
Sorry, I see what you’re saying now. I was reading this wrong, as a post marked as solution which is moved out of a category.
I’ll queue this one up to fix, though, because I think it should be a small enhancement to the work we did with the solved post.
