manyUpdate can not update null element

Hi All,

I use command:

db.StatusLogs.updateMany({“Status”: {"$exists": true, $ne: null }}, {"$set": {“Status.$[].User.FirstName”: “First”,“Status.$[].User.LastName”: “Last”}})

but i only replace if the array not have null element, so any idea if i want to replace all include null element?

{
	"_id" : BinData(3,"234234"),
	"Status" : [
		{
			"TimeStamp" : NumberLong(159924305513),
			"Status" : 0,
			"UserType" : 3,
			"User" : {
				"_id" : BinData(3,"g6HSB/23/69yCg=="),
				"FirstName" : "AAAAA",
				"LastName" : "BBBBB",

			}
		},
		{
			"TimeStamp" : NumberLong(1594349205539),
			"Status" : 300,
			"UserType" : 0,
			"User" : null
		}
	]
}
{
	"_id" : BinData(3,"1z74546=="),
	"Status" : [
		{
			"TimeStamp" : NumberLong(159921438762),
			"Status" : 0,
			"UserType" : 3,
			"User" : {
				"_id" : BinData(3,"BtuZq5f+2kWFEjJ4ere34KCKdhkA=="),
				"FirstName" : "First",
				"LastName" : "Last"

			}
		},
		{
			"TimeStamp" : NumberLong(1599218795),
			"Status" : 200,
			"UserType" : 3,
			"User" : {
				"_id" : BinData(3,"BtuZq5f+2k34WFEjJK545CKdhkA=="),
				"FirstName" : "First",
				"LastName" : "Last"
			}
		}
	]
}

I also change filter to db.StatusLogs.updateMany({“Status”: {"$exists": true }}, {"$set": {“Status.$[].User.FirstName”: “First”,“Status.$[].User.LastName”: “Last”}}) but i get the error:

WriteError({
	"index" : 0,
	"code" : 28,
	"errmsg" : "Cannot create field 'FirstName' in element {User: null}",
	"op" : {
		"q" : {
			"Status" : {
				"$exists" : true
			}
		},
		"u" : {
			"$set" : {
				"Status.$[].User.FirstName" : "First",
				"Status.$[].User.LastName" : "Last"
			}
		},
		"multi" : true,
		"upsert" : false
	}
})