There exists a potential bug in discourse-solved plugin, when any of the post in the answered topic is removed(trigger post-destroyed), whether the removed post is marked as the answer or not, the marked answer will be unanswered.
It seems weird because once someone removes an unrelated post in a topic, the topic owner will have to reselect an answer, or they will be notified by the discobot.
Maybe changing that logic to: only removing the post marked as answer will the post be unanswered is a more reasonable approach?