Support is current that pilot feature has limited to no Support. However, I will ask engineer team to take a look on this when bandwidth allowed. We are currently heads down with Winter'20 release work so please expect slow progress on the issue.

I have follow up with Support and asked to re-open the case so that we can gather required info of your org for troubleshooting. (Or you can re-open it on your end)

Does the failure happen for specific records or for all records? Is this a blocker for you to use PSG with no workaround?