When I use the ESRI Streets basemap in the Workforce Workers webmap the highway badge labels are blank when viewed on the mobile app on a phone (both Android and Apple).
The badges show up, but there are no numbers in them. The same webmap looks fine on the desktop.
If I look at the same webmap on mobile (Android phone) from AGOL it looks fine.
If I look at it on mobile from within Workforce, no highway numbers.
See attachment showing different behavior of the same webmap in Workforce vs. AGOL.