MAAS issue when power on machine

I’am having issue on power on machine via UI or cli. I’m using version 2.7 of MAAS.
Here is the maas topology.

One region controller in central DC, and multiple rackd in remote office (one per office).
Each rack controller delivers image. One subnet, one fabric, no vlan per office.

So, when i want to poweron machine via WebUI, it’s never the good rack controller associated with the subnet that launched the request, so the operation failed. I use a custom powerdriver based on old wakeonlan driver.