FindMeFollowMe group fails with cell phone in list

So I have an extension with FindMe/FollowMe enabled. I have it set for Ring Strategy of Ringallv2. The theory is to ring the extension, and if no answer after 15 seconds, continue to ring the extension along with the user’s cell phone. The Follow Me List includes the original extension and the user’s cell phone (with a # at the end of the number string). When I test this, the user’s extension quits ringing once the cell phone starts ringing. The call is essentially forwarded to the cell phone. Is this a known issue?

Running FreePBX with all of the latest updates. The extension phone is a Sangoma S500