attempt to concatenate a nil value (field 'sep') [I have workaround]

Hello. I'm getting this bug but I've add one if in template.lua and it works for me but I dont know is it good. I hope someone can help me become smarter.

How are you using the lua-language-server?

Other

Which OS are you using?

Windows

What is the issue affecting?

Completion

Expected Behaviour

Lua syntax suggestions

Actual Behaviour

No suggestion

Reproduction steps

1. Im using lua-language-server-3.12.0-win32-x64.zip at windows 11 with custom monaco editor in react app and proxy https://github.com/wylieconlon/jsonrpc-ws-proxy
3. Im just refreshing page with monaco editor
4. i'm getting error

[12:57:54.533][error][#0:script\config\template.lua:157]: script\config\template.lua:157: attempt to concatenate a nil value (field 'sep')
stack traceback:
	script\config\template.lua:157: in method 'loader'
	script\config\config.lua:66: in function 'config.config.setByScope'
	script\config\config.lua:217: in local 'expand'
	script\config\config.lua:229: in function 'config.config.update'
	script\provider\provider.lua:59: in function 'provider.updateConfig'
	script\provider\provider.lua:142: in function <script\provider\provider.lua:140>
	[C]: in function 'xpcall'
	script\proto\proto.lua:202: in function <script\proto\proto.lua:177>
[12:58:12.112][warn] [#0:script\proto\proto.lua:189]: Method [textDocument/codeAction] takes [17.689]sec. {
  _closeMessage = "Request cancelled.",
  _closeReason = -32800,
  id = 4,
  jsonrpc = "2.0",
  method = "textDocument/codeAction",
  params = {
    context = {
      diagnostics = {},
      triggerKind = 2
    },
    range = {
      end = {
        character = 0,
        line = 0
      },
      start = {
        character = 0,
        line = 0
      }
    },
    textDocument = {
      uri = "file:///MY_PATH"
    }
  }
}

and no syntax suggestion

Additional Notes

I have simply wrote it in script/config/template.lua :

		log.info(self.sep)
		log.info("----- value-----")
		log.info(value)
		if self.sep then
			log.info("----- self.sep 2 -----")
			log.info(self.sep)
			for s in value:gmatch('[^' .. self.sep .. ']+') do
				t[s] = true
			end
		end```

now it works perfect

value is always
`configuredByTheme`

### Log File

[logs_bug.txt](https://github.com/user-attachments/files/17679384/logs_bug.txt)

Start at script/config/template.lua:157 and follow the config flow through script/config/config.lua, using the supplied stack trace and logs_bug.txt. Reproduce the refresh in the Windows 11 setup if possible, then verify that completion returns without the nil 'sep' error and that the relevant config path is covered by an appropriate test.