Hi Dan. Thanks for your reply.
I had seen the SO article you referred to and and had verified that my system maxsize was sufficient to cover the date ticks from the AGOL data (I am using python 3.x).
I did stumble upon a solution to the problem, however. I used a method from the ArcREST API
arcrest.common.spatial.toDateTime()
to convert the ticks to a python date time object. I then used that new datetime object in the InsertCursor. So far, its working as expected.
Thanks again for your suggestion.