I've created a Workforce project, and can see my Dispatcher and Worker maps from the projects Overview tab. I am able to assign tasks through the Dispatcher map without any problems.
I'm using a Pixel 3 to run Workforce in the field. I can see assigned tasks, but when I click on 'Collect at Assignment' to open up Collector, I get a "Map not found: Make sure the map is shared with you." message come up.
It seems like my sharing permissions are setup correctly though, so I don't know what is going on. Any ideas on things to try??