I ended up switching from google tag manger to the GA js snippet for now and I think its working. I’m seeing events in the dashboard versus none over the weekend.
This seems to happen when uscript blocks the google analytics tag from loading, as far as I can tell. I think the change above is safe for users who block trackers.
So, tracing through the cause further, it looks like SimpleContentExperimentsPlugin::head_javascript is not being called. I’m investigating further…
