It appears that ESRI tiled basemaps for export are not getting clipped in the field maps app when a map area is created using the irregular sketch polygon tool. I have a web map setup for offline collection with an ESRI "imagery for export" basemap set. When I bring that web map into the Field Maps app and try to define an offline map area, I draw an irregular polygon map area using the Sketch Polygon Map Area button, e.g. parallel along a diagonal roadway, the basemap is not getting clipped to the map area. I am getting a rectangle box around the offline map area polygon which results in extra basemap area being cached on the mobile device, increasing the download time especially on larger offline map areas. Currently I don't see much difference between the "Sketch Rectangular Map Area" and the Sketch Polygon Map Area" tools in the Field Map app. Enabling the Sketch polygon map area to clip basemaps would make that option more useful.
