When calling an extension with FollowMe call confirmation enabled, they answer on the external number, and then perform a DTMF blind transfer to an extension with FollowMe but has call confirmation disabled, it will still prompt them to "press 1 to accept..." but as soon as they press 1 the "call is no longer available" greeting is played.
So there's two issues.
1 - Call confirmation is being prompted
2 - It is impossible to answer these calls.
Let me know if you need any further info.
I reproduced this on two systems: 1 FreePBX 13 Asterisk 13, 2, FreePBX 14 Asterisk 16.