Labels do not display in vector tile layers published in ArcGIS Online.

Workaround

1. Using ArcGIS Pro, prior to publishing the tile layer to ArcGIS Online, on the General tab, uncheck the Feature check box under Layer Type.
   1. 
2. Create a vector tile package in ArcGIS Pro and publish it as a hosted tile layer in ArcGIS Online.
   1. Open the project in ArcGIS Pro with the data.
   2. Open and run the Create Vector Tile Package geoprocessing tool. Save the tile package to the machine.
   3. In ArcGIS Online, click Content > My Content > New item. Add the tile package. 
   4. Select Add tile package and create a hosted tile layer.

Steps to Reproduce