Rebaru, rebloom on clematis is quite common, more so with type IIs but can happen with type Is. I have even had a macropetala rebloom after it was planted one spring. The seedheads from the original bloom cycle were still on the plant when I planted it in the spring. The second but smaller flush of blooms occurred in late July. This shouldn't affect its blooming next spring at all since next spring's main flush will occur on wood that hardens off over this growing season.

I just shovel pruned mine because it's pale blooms are washed out in our gray skies in spring. I have read of multiple macropetalas and alpinas reblooming in summer though.