I have a Node.js app that is creating a 'unit' in the DB under a 'building' that is saving two 'units' inside the array included in 'building'. Both of these are identical in both data and created timestamp. Anyone have an idea why the below code would be causing this to happen? I am a bit confused at it. I don't see how it would be adding two objects to the array. The code is not being run twice, I checked that with console.log() and just looking at my API logs.

await Building.findOneAndUpdate(
        {buildingID},
        {"$push": {units: unitData}},
        (err, doc) => {
            if(err) {
                logger.error(`POST unit/new save error for unit: ${unitID} - error message: `, err)
                return res.json({success: false, err, message: 'Error saving new unit, please try again'})
            }   
            logger.debug('POST unit/new save() doc: ', doc)
            return res.json({success: true, message: `Successfully saved new unit with ID of: ${unitID}`, unitData})
        }
)