If this is an isolated case, shrug it off. It could simply be a misclick. The suggested edit interface is quite risk-prone, not only because of the usual problem with two buttons next to each other, but also because decided edits scroll away so if you're fast you might end up clicking in the right column but on the wrong row.
Looking through this user's recent reviews, he rejected 4 of his most recent 90 reviews, and approved against the flow 5 times:
4 and 5 should have been obvious rejects; 3 looks like an honest mistake, and 1 and 2 look borderline.
Haim: You need to be more careful when reviewing edit suggestions. Take an extra couple of seconds on each edit to make sure you select the right button, and don't hesitate to skip if you're unsure. It's not as if you won't be reaching the 30/day limit anyway.
Shadow: a 95% approve rate isn't so surprising if someone only approves obvious formatting and English improvements and skips other cases. (Ok, that's not far from my behavior and I have a 75% approve rate, but I'm on the side of rejecting trivial edits.)