Internal trunk CID issue

I have 2 locations, connected via a IAX trunk. On site B, I have a route that specifies Site A extensions and external DID and routes through the inter-company trunk. If I dial an extension, that extension’s number and name shows up on the destination’s endpoint. However, If I dial a DID, CID on Site A’s phone shows one of the Site A’s local DIDs. Always the same regardless of the actual DID dialed.

Site B’s CID is set to Site B’s number.

What can be causing this?