They ZE-326's by any chance?
I got those in the same size and they do the exact same thing. Two of my buddy's said they're most probably the tires. I aquaplaned in them on a slight incline when just taking off normally. So I never rev near 2k in first when it rains. And yes, they dont grip at all. Mine tends to lose front end traction on low speed cornering or long bends.