If you find a bug but it has already been reported by another tester, you unfortunately may not submit the same bug again, but what you can do is to submit a reproduction! Reproductions are useful for customers because they indicate which environments are concerned and if the problem is device-specific or not. Hence, it gives customers a better idea how severe the bug is.
To reproduce a bug, follow the same steps as described by the original tester in his/her report. If you experience the same bug as the original tester, we call that a positive reproduction. If you cannot reproduce the bug despite following the same steps, we call it a negative reproduction.
A negative reproduction should show that the function works on your device, so that you don't experience any bug. If you experience a different bug, you should instead submit a bug report or reproduce another tester's bug report who submitted that problem.
The following rules apply for reproduction attachments:
A screencast is required.
Your screencast should be no longer than 15 seconds. Showing the action that triggers the bug is enough in most cases.
Only in rare cases, if you cannot show the bug-triggering action within 15 seconds (e.g. when the page is loading endlessly), your screencast may be longer but not longer than the screencast from the original tester.
Your screencast must include the current date and the URL bar when testing a website.
When reproducing an app crash, upload a crash log file in addition to your reproduction screencast. Your screencast has to correspond to the attached crash log, i.e. timings must be coherent.
Reproductions that don’t comply with the rules will be rejected, e.g. if your screencast is too long or if it shows unnecessary steps.
You can see the "Can you reproduce this bug: Yes or No" button if:
while the test is running
only for other testers' functional bug reports
only for reports that have not been reviewed by the customer
only if the maximum number of reproductions for the bug report has not been reached (depends on the customer's purchased plan)