An error occured when trying to validate permissons

This error message keeps occuring on my extension. I am using a custom messages file to tweak some bits to my personal preference.

It also gives me this error message:
`queryPermissions/</httpRequest.onreadystatechange@moz-extension://3bf0f194-df0c-4fa0-847d-e06631c43ddf/src/content/permissionCheck.js:50:21`

This happens randomly and I'm not sure how to trigger it.