If you’re seeing random sites pop up with transparency warnings, it’s due to a new Chrome rollout of that requirement. However they’ve allegedly rolled it back, but Chromium users may be stuck on the strict version.

https://bugs.launchpad.net/ubuntu/+source/chromium-browser/+bug/1641380

https://bugs.chromium.org/p/chromium/issues/detail?id=664177

https://knowledge.symantec.com/support/ssl-certificates-support/index?page=content&id=ALERT2160&pmv=print&actp=PRINT

https://sslmate.com/blog/post/ct_redaction_in_chrome_53