Earlier quoted context omitted.
If a website bug is not easily solved, first order of troubleshooting is to disable all extensions. Devs don't often think an extension could be causing the problem, but extensions can do wild things to a webpage. I've caught a few bugs caused by extensions this way.
This is not an extension. It's some other kind of plugin or weird hook. They tried disabling all extensions first thing.
Sorry but there is no rule that every comment made about an article must be specific to the outcome of an article about troubleshooting. I can comment about other things covered in the article too.