ONTAP triggers Consistency Points (CPs) for multiple reasons, and you can read up on them here: https://kb.netapp.com/app/answers/answer_view/a_id/1001446 I would stress that CPs are a normal function of ONTAP, ensuring data consistency and improving write performance. The only CPs that would be of concern in normal operations would be "B" or "b", which indicate that the controller is seeing incoming write workload higher than its ability to flush data to disk, although even seeing these type of CPs may not be a concern if write latency is not elevated.
In this case, the "U" type CPs are being generated by clients flushing asynchronous writes to the controller, and are a normal part of controller operations.
-Ken Mencher
Lead EE, Americas Performance