Follow-me firstnotonphone strategy no longer works as expected

I asked about this in the forum at http://community.freepbx.org/t/has-the-operation-of-follow-me-firstnotonphone-strategy-changed-in-freepbx-13/38270 and it was suggested I create a ticket. As I posted there:

I have been working on setting up a new install of FreePBX 13.0.190.7, copying all my settings and configuration over from a FreePBX 2.11 system. When I tried to bring it up "live" for the first time, I noticed that extension to extension calls were going straight to voicemail if the first phone in a follow-me group was off-hook. For example, let's say I am calling extension 121 from extension 120, and the follow-me list is set to

121
120
122

Now if I take extension 121 off-hook, and place the call to extension 121 from 120, extension 122 should ring, and that's what happens under FreePBX 2.11. But under FreePBX 13 the call goes straight to voicemail, which is the no answer destination. This is using the firstnotonphone strategy. As far as I can tell, the configurations for the extensions and follow-me are identical on both systems, except for new fields added in 13 which are at their default settings, and the extension NAT mode is set to no when for some reason it had been set to yes on the 2.11 system - it's an internal extension so I doubt that would make a difference.

Has something changed in the logic of the firstnotonphone strategy between 2.11 and 13?