Super big thanks for the note back, and so quickly. Given your success, you prompted me to try a couple of things, first using zedi, which showed the exact same problem, and to try more clusters. I've got 3 with raid tec all running ontap 9.0P1. Two of them fail, and one works just fine, so that's no good, however, it did lead me to the actual problem. The raid tec aggregates are new, and on two clusters, they just so happen to be the 21st+ aggregates. By default, aggr-get-iter returns only 20 aggregates. I added a max-records and it's all good.
If anyone else happens to run into the problem, the solution is shown below: