Python Firebase Admin SDK Listener sometimes throws Bad Gateway errors after DB is updated

### [READ] Step 1: Are you in the right place?
Yes

### [REQUIRED] Step 2: Describe your environment

* Operating System version: cos-stable-101-17162-40-5
* Firebase SDK version: latest?
* Firebase Product: realtime database, admin SDK
* Python version: 3.8
* Pip version: latest?

### [REQUIRED] Step 3: Describe the problem
I have a database with customers data in it. When a new customer is added, a Firebase function triggers and updates '' to [user.uid]: to represent credits in my system. I have a google cloud VM that has an admin sdk database listener setup. Every month or so, after a new customer signs up, all of my listeners will randomly throw an error. The error I am seeing is:
**requests.exceptions.HTTPError: 502 Server Error: Bad Gateway for url: https://-default-rtdb.firebaseio.com/.json**

I am using the realtime listener described in this stack overflow post top answer:
https://stackoverflow.com/questions/49863708/python-firebase-realtime-listener

#### Steps to reproduce:
Hard to reproduce, but I can also provide my project ID and exact times for the issue so that the Firebase team can look into server-side logs to see what the issue might be.

#### Relevant Code:
```
from firebase_admin import db
def exampleFunc(event):
try:
print(event)
except Exception as e:
return

#in startup function
listener1=db.reference('').listen(exampleFunc)
listener2=db.reference('').listen(exampleFunc)
```