If you click on the share icon on the artist page in the app, it will just share the artist name instead of a link to the artist page.
I tried to work around this by just just going to the mobile site on my Android device so I could copy the the link from my browser, but it auto opens the app when I search for a city or artist on the home page. I ended up just googling “street art cities + artist name” and then copying the link from the Google search results. It worked in the end but was a bit of a pain 