Web SDK (alloy.js) isn't populating identityMap with ECID
I have a simple page I built to do some testing with collecting data via the Edge network using Alloy.js. The ECID seems to be getting set on the page correctly but when I look into the datasets, the identityMap field doesn't seem to contain the ECID. I also don't see the ECID or the identityMap field anywhere in the HTTP request.
It's my understanding that the ECID should autopopulate into identityMap. Have I missed a configuration step or is there possibly some other common reason why ECID is not being passed in?
What am I missing?