Updateone to $inc a number returns "modifiedCount": 1 but the value never changes in document

Working with Data
,
6

Thanks for the help @steevej and Stennie, I was with the mongo support chat for this same problem, because they told me to do the same stuff.

This is the mongoDb information:
MongoDB 4.4.11 Enterprise
The driver is the nodejs driver version: 4.1.1

I changed my code and use aggregation and that work fine. But the normal updateOne didn’t. I ran the code from the shell and had the same results with updateOne command. The modified flag says the change was made but when I refresh in Compass the information isn’t change.

In my react app the code is:

import clientPromise from "../../../lib/mongodb";

const client = await clientPromise

const database = client.db('db_name');
await database.collection('payments')
   .updateOne({ “contract”: 'C-7806' }, { $inc: { “Balance”: -200 } }, {upsert: true})
   .then(result => {
       res.json(result);
   })

In the mongodb shell:
db.payments.updateOne({ “contract”: 'C-7806' }, { $inc: { “Balance”: -200 } }, {upsert: true})

The query returns:

{ “acknowledged”: true,
“modifiedCount”: 1,
“upsertedId”: null,
“upsertedCount”: 0,
“matchedCount”: 1 }

To make sure I wasn’t adding extra documents, I had only one document in the collection and same result. No new document and the one existing had modifiedcount: 1 but still no change in the information.

Now with aggregation it is working, but I’m seeing that sometimes the $inc works and other times it doesn’t and I don’t understand why.

This is my aggregation code:

{
   '$set': {
       'Balance': {
              '$subtract': [
                   '$Balance', amount
               ]
        }
    }
}

I run in Compass and again sometimes work and sometimes not… and also if I edit the information in Compass, then original value of Balance is set instead of keeping the value set by the aggregation query??

Could be a bug?