### [REQUIRED] Describe your environment * Operating System version: iOS Version:13.3.1 * Browser version: Mobile Safari Version:13.0.5 * Firebase SDK version: 7.9.1 * Firebase Product: firestore ### [REQUIRED] Describe the problem #### Steps to reproduce: I can't reliably reproduce it so not entirely sure what specifically causes it but here is the Sentry error: https://sentry.io/share/issue/03f7cacb9f394cdd9867f13ad40345d8/ Once this errors subsequent requests start failing like this: https://sentry.io/share/issue/aab1ab9ce88e4d50a3e40edbc27c0700/ #### Relevant Code: This is my firebase setup: https://github.com/AugustinGrigorov/vocabulary-builder/blob/master/src/utils/firebase.js