Ring group only rings one endpoint of multi-endpoint extension

FreePBX: 12.0.51, Asterisk 13.2

My pjsip extension has multiple devices. I have one at my desk, one at my desk at home, a cordless phone, and a soft phone on my cell phone. I have a ring group for a phone in our building lobby. When someone uses this phone to call the ring group, only my main desk phone rings. The other phones never ring. However, call the extension itself (114) and all devices ring just fine, as expected.

Aside from being unable to answer from other phones, I have a feeling that one day the phone that rings is going to be the phone I’m not next to, and I’ll miss something important. Any way to fix this?