Call forwarding issue on RCF'd DID

We have a handful of non-local numbers remote call forwarded to local DIDs setup as inbound routes to extensions in FreePBX (5.211.65-16, Asterisk 11.12.0). When these extensions are forwarded, calls to the RCF’d numbers ring once, then go to voicemail. Calls to the local number assigned to the extensions forward as expected.

Any ideas?

What voicemail are they going to?

When the extension is forwarded, the line rings once, then goes to the voicemail for the extension.