When the PDF name contains diacritics and is used as an attachment in the map image layer, it downloads automatically instead of opening it in a new tab when attempting to view it on Map Viewer
This defect is logged against a version of the software which is no longer supported. The issue is not reproducible in newer versions of ArcGIS Enterprise Map Viewer. If experiencing this behavior, please reach out to Esri Support Services as a new reproduction case is needed to continue the investigation.