We also had issues with the ad blocker, and after turning it off it worked perfectly. However, since a week or so the addon has stopped showing up in the PRs (bitbucket cloud).
I cannot see a request being fired similar to the one @pschoen shows in his screenshot, but we do get a spinner saying the addon is loading but then it just disappears and shows up blank as originally showed by @pschoen. I went through all requests being fired and none of them seems related to the SonarCloud addon.
Loading: After:
Looking in the console, these errors show up, but I have no idea if they are related to the SonarCloud addon: