Steps to replicate the issue (include links if applicable):

• Install Wikipedia Article Recommender extension
• Visit https://en.wikipedia.org/wiki/Special:CommunityConfiguration/GrowthSuggestedEdits or the the Block User form
• Check and uncheck the checkbox

What happens?:

The checkbox UI is not displaying as expected:
Community Configuration screenshot

Block User form

What should have happened instead?:

Other information

• Only tested on Chrome.
• The issue resolves when you remove the Wikipedia Article Recommender extension.
• Tested and reproduced by another tester (Urbanecm_WMF)
• Not all checkboxes are affected for some reason. The "Watch this page" checkbox on editing is unaffected, so are checkboxes in my preferences. But the issue is not Growth-specific.