I'm going to call bullshit right here, because I've just look at the list of your posts and only your latest post has been downvoted by said persons out of all posts you've made in the last months. ONE post. They are in there right to downvote your posts just as everyone who upvoted is in their right to upvote. Likely they decided that the content you make was not worth the reward you were getting and adjusted it because they are able to.
You aren't being targeted, you aren't being bullied. there is not flaw in the system. Everything is working as intended.
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They literally took back their downvotes on a few of my posts since I posted this. Not bullshit. One of them was regularly commenting before with troll shit that had nothing to do with the post too. A couple months ago they did it to every post for about 3 weeks. Now they have begun again, and this time it appears some of the votes seem to have been taken back somehow. Not sure how it works.
Well the thing is to take back a downvote means to send out a transactions nullifying the previous one, I can't find any such transactions on their accounts.