I am using ArcGIS Pro version 2.5. From the pictures below, I have the pop-up configured and it displays correctly in ArcGIS Pro.
I have read that you can publish layers and the configured pop-ups will follow to Portal which my version is 10.7.1.
My workflow is like the first post's for publishing. Share tab -- Publish web layer -- I am referencing registered data -- Publishing both Feature and Map Image. I do not have version issues like the second post with my Portal being above 10.6.
After the publish goes though, when I open the web map and load the data in, none of the pop-up configuration transfers. The custom text, selection of fields, and expressions do not publish. I have tried this with the image layer, the feature layer, registered data, and hosted data.
Is there something that I am missing?