SYSTEM_ERROR: system encountered unexpected error. Function killed. Cloud functions - node.js

Question

When I looked through logs from Firebase cloud functions, I noticed that some functions have an error in logs with a description of "SYSTEM_ERROR: system encountered unexpected error. Function killed.", Until yesterday, this behavior was not, here is one of these functions. How can I fix it?
const functions = require('firebase-functions');
const admin = require('firebase-admin');
module.exports = functions.database.ref('/cards/{cardID}/interestedUsers').onWrite(event => {
const cardID = event.params.cardID;
console.log("interestedUsers", event.data.val(), cardID);
var currentInterestedUsers = [];
currentInterestedUsers = event.data.val();
var previousInterestedUsers = [];
previousInterestedUsers = event.data.previous.val();
if (event.data.previous.val() && currentInterestedUsers) {
var isNewPendingRequest = false;
if (currentInterestedUsers.length < previousInterestedUsers.length) {
currentInterestedUsers.forEach((interestedUser, index) => {
const interestedUserVal = interestedUser.val();
const isApproved = interestedUser["isApproved"];
console.log("result", interestedUser.val(), interestedUserVal);
if (isApproved == false) {
isNewPendingRequest = true;
}
});
}
if (isNewPendingRequest == false) {
const cardRef = admin.database().ref("cards").child(cardID);
const setupIsNewPendingRequestPromise = cardRef.update({
"isNewPendingRequest": false
});
return Promise.all([setupIsNewPendingRequestPromise]);
};
return console.log("interestedUsers deleting");
};
if (event.data.val() == null) {
console.log("event.data.val() == null");
const cardRef = admin.database().ref("cards").child(cardID);
// check card
const cardCheckPromise = cardRef.once("value", function(cardCheckPromiseSnap, error){
if (error) {
return console.log("cardCheckPromise", error);
};
if (cardCheckPromiseSnap.val()) {
const checkCardID = cardCheckPromiseSnap.val()["id"];
if (checkCardID) {
console.log("checkCardID", checkCardID);
const setupIsNewPendingRequestPromise = cardRef.update({
"isNewPendingRequest": false
});
return Promise.all([setupIsNewPendingRequestPromise]);
} else {
return console.log("checkCardID == null");
}
} else {
return console.log("cardCheckPromiseSnap.val() == null");
};
});
return Promise.all([cardCheckPromise]).catch(function(cardCheckPromiseError){
console.log("cardCheckPromise error", cardCheckPromiseError.message, cardCheckPromiseError.messageId)
});
}
return console.log("just update or adding a new interested user");
});

Answer 1

You can try re-deploying your app.

Answer 2

Likely a GCF outage. There was one today and yesterday. These errors were being thrown during the outage.
Solution
Take a break and wait for the cloud to heal. Contact GCP Support if you've purchased support.