Reproducing The Issue
Reproducing the issue is sometimes a very tough game. Some issues are happening because of the local settings of the person who created the report. Geographical location, preferences choices, web extensions and add-ons, OS, network constraints, logged on the services, devices and many other parameters are all possibly the source of the breakage as perceived by the reporter.
Try your best to understand the report and reproduce the issue. If you have a doubt, reach out someone from the project to help. You may wish to add a screenshot if one was not provided, or if you are seeing different results from the one that was provided. Think of yourself another bug reporter.