IVR direct dial, just real extensions?

When direct dial is enabled in IVR , I can just dial a real extension number, if I dial a queue nuber or a remote pbx extension it doesn’t work (no valid answer received).
Anyway, if a queue is a destination of IVR dialed digit , it works, and more, if queue contains a remote pbx extension it works too.
Is this an expected behavior ?

Did you read the IVR guide yet?
PBX GUI : IVR Module User Guide (sangoma.com)

Sounds right.