I don't blame you, been on reddit for a long time.

Not saying this is necessarily a case of real manipulation, but I've had a number of "fishy moments" where based on the sub, the topic, and the immediacy of the downvotes/upvotes where it appears that something odd is happening. It could also always be chalked up to some crazy person with an agenda who uses alts to engage in vote manipulation. But we know for a fact social media manipulation happens, we know for a fact vote manipulation on reddit happens (based on many reports from people who have actually done it), so anyone who dismisses it as outright impossible is definitely in the wrong.