have you checked out the recent Meta post Why has my Reputation Score Suddenly Changed?
Do you know which question it was? The moderation team is currently doing a substantial prune of falsified content, where we're having to delete more than we usually would under regular circumstances. It's likely that the Question in view here was asked, answered and accepted by a single user under the guise of separate accounts, and was not a genuine question. We're trying to preserve high quality or useful content wherever possible, but are having to balance that with other concerns.
Please rest assured that this is a "one time" activity and we are otherwise extremely cautious about removing content. Please do raise a Flag or post a Meta question like this if you have any concerns.
Edit: Sorry, this post wasn't one of this batch - have found it and undeleted so you can remediate if you want. Normally we would add a "post notice" and give you time to address before Deletion - apologies for not giving you more notice. Thanks for flagging.