OM_EVENT_GENERATE
I believe you have no DFM integration in your snapcreator configuration file.
These LUN online/offline events are detected by DFM to report any production LUNs going offline/online.
If you know how fast your cloned luns go offline and come back online, you may be able to tune a setting in DFM that can ignore these fast events.
You can tweak the interval from OM like below.
setup menu > Options > Edit Options: Monitoring > LUN monitoring interval, Fiber Channel monitoring interval, and SAN Host monitoring interval
But, you will run into risk of not reporting other production LUN events.
I have reached out to the OnCommand team as well on this to know if they have any other available option.