Bookmarking Units (suggested by Mappers) on iPads

Hello, I am trying to bookmark units (suggested by Mappers) onto an iPad. I was able to do it on my daughter's iPad, but my son's iPad says "open in browser This content isn't available in our app". BUT the browser version doesn't seem to have a "bookmark" option.

They are the same version of the app, and I took the identical steps. 

I actually don't even need to bookmark the units if there is a better way to save the suggested full units from Mappers to their accounts on their iPads?

Thanks so much!