I tried with Py4J versions 0.10.9.5, .3, and .1. None of those versions worked. I also tried upgrading the runtime to 13.0 and 12.1 and saw the same issue. The 13.0 runtime upgraded Py4J to 0.10.9.7 and that didn't resolve the issue. The error stayed the same in all cases.

Our Databricks is deployed in a private VNET for Hippa compliance. I'm wondering if that is related.