Pop-up media images of a web map with more than 100 characters in a hyperlink field are displaced in the Detail widget in ArcGIS Dashboard when open in Internet Explorer.
The issue is non-reproducible when testing with ArcGIS Online on December 2020 release and it is related to the deprecation of support for Internet Explorer browser.
https://www.esri.com/arcgis-blog/products/arcgis/announcements/so-long-internet-explorer-11/#:~:text=Customers%20on%20ArcGIS%20Enterprise%2010.8,to%20customers%20using%20ArcGIS%20Enterprise.