whenever a cluster being updated to a version that required accepting potential risks, clusterversion is preserving "acceptedRisks" under history. 
however an attempt to update the cluster to a version blocked by Precondition checks (ReleaseAccepted=False) is causing a previous acceptedRisks to disappear, losing the information on a previously accepted risks.

4.17 (possibly elsewhere as well)    

always?

    1. create acceptedRisks (such as updating explicitly to non-recommended)
    2. target another version which is expected to fail on Precondition
    3. observe acceptedRisks disappear from .status.history[]      

    the risk information is lost from history

information is preserved. unaccepted release have no effect on acceptedRisks