ArcMap Viewer basemaps require login

[rgmingo]

Web map created with basemaps in the "new" Map Viewer create a login requirement even if map is shared publicly (and even if the webmap is the only layer in the map). If I open the webmap in Map Viewer Classic change the basemap, and then reopen it in the "new" Map Viewer then I can share it just fine no login requirements.  Any ideas how to fix this?

[BernSzukalski]

It would be helpful to know which basemaps you are having issues with. Just about all, save for two country-specific basemaps from Esri distributors, are completely public. Here's the list of Esri basemaps, all public:

https://livingatlas.arcgis.com/en/browse/#d=2&categories=Basemaps&type=maps&cont=true