Get Device Footage / Get all Devices Footage not working using JSON-RPC on 6.1+

Hello,

I am working on a software where we want to display the available footage for a specific date range, we have been using JSON-RPC through WebSocket successfully until now. But the footage commands does not seem to work properly.

https://our-server:7001/rest/v4/devices/device-id/footage?startTimeMs=1782999473000&endTimeMs=1783031410000

returns footage as expected

[
  {
    "serverId": "server-id",
    "startTimeMs": 1782999801763,
    "durationMs": 13000
  },
  {
    "serverId": "server-id",
    "startTimeMs": 1782999875762,
    "durationMs": 12600
  },
  ...

Now if I use the NX VMS JSON-RPC WebSocket Testing Tool (Or our own app) with the same query:

{
 "id": 12,
 "jsonrpc": "2.0",
 "method": "rest.v4.devices.footage.one",
 "params": {
   "id": "device-id",
   "startTimeMs": 1782999473000,
   "endTimeMs": 1783031410000
 }
}

The server returns empty:

{"jsonrpc":"2.0","id":12,"result":[]}

Using rest.v4.devices.footage.all instead gives a slightly different result, but still empty:

{
 "jsonrpc":"2.0",
 "id":15,
 "result":{
  "device-id":[]
 }
}

Using rest.v4.devices.footage.all without passing the device id works, but it returns thousands of results and takes a while to retrieve, it's not a viable solution for our project. 

This looks like a bug but could it be something else? Permission? Server configuration?