Usage patterns
〈物〉が不完全だfor something to be incomplete/imperfect
This data is incomplete, so we can't present it yet.
不完全な〈物〉an incomplete/flawed thing (e.g. information, plan, system)
It's dangerous to make a judgment based on incomplete information.
〈事〉のまま不完全に終わるto end while still incomplete/unfinished
The construction work ended up unfinished and incomplete.