Plugin is causing issues in Gutenberg editor

When this plugin is enabled on our site, it’s causing this weird issue with saving – basically, if you make any edits to a page, it reloads the page during the save/autosave and any changes you made are gone. Disabling this plugin resolves the issues. We have the latest version of the plugin, WordPress, and I’ve double-checked the items in the pinned post at the top of this support forum.

JS console shows the following relevant messages:

HubSpot plugin – IntegratedAppEmbedder initializing for: {
“app”: “integrated-plugin-proxy”,
“baseUrl”: “https://app.hubspot.com”,
“route”: “https://app.hubspot.com/integrated-plugin-proxy/7881635?integration=wordpress”
} console.js:32

HubSpot plugin – IntegratedAppEmbedder send StartApp message for: integrated-plugin-proxy console.js:32

Uncaught (in promise)
Object { code: "invalid_json", message: "The response is not a valid JSON response." }
?
code: "invalid_json"
?
message: "The response is not a valid JSON response."
?
: Object { … }
??
defineGetter: function defineGetter()
??
defineSetter: function defineSetter()
??
lookupGetter: function lookupGetter()
??
lookupSetter: function lookupSetter()
??
proto:
??
constructor: function Object()
??
hasOwnProperty: function hasOwnProperty()
??
isPrototypeOf: function isPrototypeOf()
??
propertyIsEnumerable: function propertyIsEnumerable()
??
toLocaleString: function toLocaleString()
??
toString: function toString()
??
valueOf: function valueOf()
??
: function proto()
??
: function proto()