Unfortunately the blockchain is immutable.....and I think what happened was you didn't use the hash tag originally in your post so I saw the post and upvoted it since it was in my feed, but when I went looking for posts with the tag, it must not have had it. Since that was a requirement and those were the posts I was looking for, yours was overlooked.
It drove me a little crazy trying to figure it out but I am pretty sure that is what happened. On the bright side powering up is still a good thing and HIVE coin and the HIVE blockchain is stronger for it.

Thank you for doing your part @ninahaskin in support of the blockchain and hopefully I can help make up for this by continuing to support your posts when I see them. Take care.