TypeError inputTypes contains (special characters)

Hi @jsheffers, I followed your steps & unable to replicate the issue in drupal9.5. Can you please tell, which drupal version are you using ?
Attached a screenshot

10.1.5

Confirmed this happens on multiple themes (my custom theme, and Olivero)

I don't think this code is coming from Mercury Editor.

The error in the screenshot says contains is not a function which is true. There is no native contains method on an Array in JS. From the code, it looks like contains() should be includes().

I did a search through the codebase and couldn't find this code anywhere in the module so it must be coming from another theme, module or 3rd party script.

I narrowed this down to not passing attributes through the paragraph twig template. Not sure exactly where it's coming from, but if the attributes are passed properly, the issue goes away.