Firebase Function & Storage has stopped working

I wrote two functions (~ 07/20/21) using the FB admin SDK to upload a file to FB Storage. It worked for 300+ uploads. I came back to it yesterday (08/11) and it no longer works, and has had no code changes (that I know of).

The FB functions Logs are saying app ReferenceError: bucket is not defined at Object.writeFileToFirebase (/workspace/uploadUtils.js:12:18) The storage bucket is defined in my ./firebaseConfig.js in accordance with the documentation.

const firebase = require('firebase')
const functions = require('firebase-functions')
const admin = require('firebase-admin')
const firebaseConfig = require('./firebaseConfig.js')
firebase.initializeApp(firebaseConfig)
admin.initializeApp(firebaseConfig)
const bucket = admin.storage().bucket()

And my two functions are exported from uploadUtils.js

async function writeFileToFirebase(filename, mimetype, filebuffer) {
    const file = bucket.file(filename)
    const filestream = file.createWriteStream({
        metadata: {
            contentType: mimetype
        }
    })
        
    await filestream.end(filebuffer).catch(functions.logger.log(err))
    
    return
}

async function createThumbnail(newthumbname, mimetype, filebuffer) {
    const file = bucket.file(newthumbname)
    const thumbstream = file.createWriteStream({
        metadata: {
            contentType: mimetype
        }
    })

    const gm = require('gm').subClass({
        imageMagick: true
    })
    
    gm(filebuffer)
        .resize(240, 240)
        .toBuffer('jpg', (err, thumbbuffer) => {
            thumbstream.end(thumbbuffer).catch(console.log(err))
        })
    
    return
}
exports.writeFileToFirebase = writeFileToFirebase
exports.createThumbnail = createThumbnail

Line 12 from the err msg is the const file = admin.storage().bucket()

My declaration of bucket is at a higher scope than the function call. And I'm using the default bucket I've specified in the firebaseConfig.js.

Can anyone tell me what's wrong with my bucket declaration? Or is my problem elsewhere?