javascript – Cannot read properties of undefined (reading ‘show_ui’) Error on WordPress Post Editor


We’re getting the following error on our Block Editor when trying to edit a post:

TypeError: Cannot read properties of undefined (reading 'show_ui')
at i (
at lf (
at Le (
at Pj (
at di (
at Nj (
at sc (
at gf (

Here are the details on how our WordPress is configured:

  1. Our WordPress sits behind an AWS Firewall and our resources are served through Cloudfront.
  2. We have a staging site identical to the production environment minus Cloudfront and we are not seeing this error on the staging site even though all the plugins and WordPress version are the same.
  3. The oddest thing about this error is that we are only seeing it when trying to edit a post and not when trying to edit a page.
  4. A lot of solutions suggest changing a configuration on a NGINX server BUT we are not running our WordPress on NGINX. We’re just using Apache2 and PHP-FPM.

Here’s what I’ve tried:

  1. I’ve tried clearing the CloudFront, Site and Browser cache as suggested in this article:
  2. I’ve added a rule in the WAF/Cloudfront to not cache resources from the following URL:*
  3. I’ve reviewed some PHP changes to no avail.

It is getting frustrating as I am not able to pinpoint to the exact problem(I am not familiar with React or its problems). It’s also frustrating that many of the solutions assume that there will be a NGINX server. Some help would be appreciated. If this is really a cache problem then kindly suggest what exceptions to add.

Talha Imam 9 months 2022-04-22T16:42:25-05:00 0 Answers 0 views 0

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