Another field changes type

[bgencacat]

• Laravel-mongodb Version: dev-develop
• PHP Version: 7.4
• Laravel: 7.28.2

Description:

When I update gadget <Document>, even if I not set balloon being converted from <Document> to [Array]

{
    balloon: {},
    gadget: {
        "gadget-paintballgun": NumberInt("40"),
        "gadget-batblaster": NumberInt("30"),
        "gadget-woolfountain": NumberInt("30"),
        "gadget-firework": NumberInt("40"),
        "gadget-kaanumayparty": NumberInt("20"),
        "gadget-hook": NumberInt("20"),
        "gadget-blockcannon": NumberInt("30"),
        "gadget-explodingsheep": NumberInt("30"),
        "gadget-enderpearlbus": NumberInt("20"),
        "gadget-waterwave": NumberInt("10"),
        "gadget-firewhip": NumberInt("10")
    }
}

This is how I update
$user->globalPlayer[$gadget] += $amount;

I dont want to change type of empty "balloon" document. What should I do? (It does it to all empty <Document>s)

Thank you.