Merging doesn't appear to work with load_file method but does with settings=[] in the constructor

[Hammit]

Bug Description
When I have multiple settings files I want to merge into one settings object, I can successfully merge using the settings kwarg in the Dynaconf constructor, however, when I try merging using load_file I don't get any merging behaviour.

To Reproduce

1. Having the following folder structure

2. Having the following config files:

Config files

./tests/configs/app.test.json

{
  "customers": {
    "a": {
      "apps": ["a", "b"],
      "databases": {
        "a": {
          "name": "b"
        },
        "b": {
          "name": "c"
        }
      }
    },
    "b": {
      "apps": ["a", "b"],
      "databases": {
        "a": {
          "name": "b"
        },
        "b": {
          "name": "c"
        }
      }
    }
  },
  "server": {
    "host": "example.org",
    "port": 443
  }
}

./tests/configs/app.merge.json

{
  "customers": {
    "a": {
      "apps": ["c", "d"]
    },
    "b": {
      "apps": ["e", "f"],
      "databases": {
        "name": "d"
      }
    },
    "c": {
      "apps": ["a"],
      "databases": {
        "name": "a"
      }
    }
  },
  "server": {
    "host": "example.org",
    "port": 443
  }
}

4. Having the following app code:

Code

./app.py

from dynaconf import Dynaconf
from dynaconf import loaders
from dynaconf.utils.boxing import DynaBox


config = Dynaconf(
    merge_enabled=True,
    settings_files=["./tests/configs/app.test.json", './tests/configs/app.merge.json']
)


data = config.as_dict()
loaders.write('/tmp/config.json', DynaBox(data).to_dict(), merge=False)

config2 = Dynaconf(
    merge_enabled=True,
    settings_files=["./tests/configs/app.test.json"]
)

config2.load_file('./tests/configs/app.merge.json')

data = config2.as_dict()
loaders.write('/tmp/config2.json', DynaBox(data).to_dict(), merge=False)

Expected behavior
I would expect to be able to save both merged configs and have identical files. load_file should merge the same way that settings_files does

Environment (please complete the following information):

• OS: WSL2 Ubuntu 22.04
• Dynaconf Version: 3.2.4
• No frameworks

Additional context
I have tried adding dynaconf_merge in various places in the file to merge without success
I can't get load_file to merge