Unfortunately it appears @bakedsalty declined upvotes on their posting. There doesn't seem to be any method in the API to weed this sort of thing out.

I cannot understand why @bakedsalty would pay @upme for an upvote and have not only the payout declined, but the ability to even upvote the posting completely declined which totally breaks it for anyone curating whether by hand or by bot. But that appears to be the case here.

I have filters in place to prevent sarabot from considering upvoting posts that have payouts declined, but I never even knew it was possible to decline upvotes all together. Sarabot viewed the exception being thrown as a network issue and just kept retrying :( I guess I have to trap this specific error and add these to my blacklist. Sorry @bakedsalty , I don't know what you were doing when you did that, but it's very strange.