Hide post doesn't work on subscriptions dashboard

Expected Behavior

Clicking hide post should hide the post from the dashboard

Actual Behavior

Hide post does not hide the post and an error is logged in the console

https://i.imgur.com/jo45o8s.png

Steps to Reproduce the Problem

1. Login to notify
2. Navigate to your subscriptions
3. Click the more options icon (Three vertical dots)
4. Click 'Hide Post' and observe as nothing happens and an error is logged in the console.

Specifications

• Browser: Chrome Version 74.0.3729.169
• Operating System: Windows 10