Can't output array correctly in JSON

Question

I am reading from CSV file and trying to create JSON structure similar to something like this, the connections property are from 3 columns combined (namely online, mirror and shared), I am combining them into one array as connections in JSON. I don't know why I am not getting the correct format of property with an array.

{
  "connectionmap": [
    {
      "Environment": "abc",
      "connections": ["x1", "x2", "x3"]
    },
    {
      "Environment": "def",
      "connections": ["y1"]
    }
  ]
}

Currently, my code is this:

function connectionPointsGenerator {
    Param(
        [Parameter(Mandatory = $true)]
        [string]$CsvPath,
        [Parameter(Mandatory = $true)]
        [string]$OutPath
    )

    $Json = Import-Csv $CsvPath | ConvertTo-Json
    $JsonObject = $Json | ConvertFrom-Json 
    foreach ($env in $JsonObject) {
        [array]$connections = @()
        $connections += "$($env.online)"
        if ($env.mirror) {
            $connections += "$($env.mirror)"
        }
        if ($env.shared) {
            $connections += "$($env.shared)"
        }
        Write-Output "$($connections.GetType())"
        $env.PSObject.Properties.Remove("online")
        $env.PSObject.Properties.Remove("mirror")
        $env.PSObject.Properties.Remove("shared")
        $env | Add-Member -MemberType NoteProperty -Name "connections" -Value $connections -PassThru | Out-Null
    }
    $hash = @{}
    $hash.Add("connectionmap",$JsonObject)
    $hash.connectionPointMapping.dit
    $FinalJson = $hash | ConvertTo-Json | Out-File $OutPath
}

This is what I am getting:

{
  "connectionmap":  [
    {
      "Environment":  "abc",
      "connections":  "x1 x2 x3"
    },
    {
      "Environment":  "def",
      "connections":  "y1"
    }
  ]
}