I’ve responded to you directly via e-mail, but just in case you missed my message:
We’ve removed floated share buttons from appearing on mobile because we found that they overlap text on a page, making it difficult for readers to view content. However, If the screen on your device is over 400 x 700 pixels (e.g. tablet), then your floated share buttons will appear in portrait or landscape mode. At this time, there’s not a way to enable the floated share buttons for mobile.
Let me know if you have anymore questions about this. I’m happy to help!