Before filing bug reports or feature requests in the Issue Tracker, it is recommended first to search for similar ones, post in the relevant Forum if none is found, so others may help establish a bug as genuine, provide ideas and second opinions for new features, and gather concensus.
Include a link to such discussion when creating the Issue in Issue Tracker.
The role of Issue Tracker on musescore.org is to triage before opening an issue on github. The expectancy is that the .org tracker will at some point undergo some changes to facilitate it linking to github issues, source.
Once the issue is referred/reposted to github, the one on musescore.org will be marked Duplicate to unclutter the triage system.
Please include as much of the following information as you know and limit each issue to one report:
Attach the score that shows the problem, at least a minimal example —use the "File attachments" option at the bottom of the page, just above the Save and Preview buttons when you're typing your post.
Fill in the correct issue detail field, eg If you did not gather any shared experience in forum, use Frequency: Once. Once the issue is referred/reposted to github, the one on musescore.org will be marked Duplicate to unclutter the triage system, jump to triage above.
When you write a comment in a forum topic, you can refer to an issue in the issue tracker using the following notation: ´[#number]´
That way the link in the comment will include the issue title and reflect the current status of the issue. Furthermore, it'll lead to the forum topic being listed in the issue itself.
Type [#153286] get #153286: Change instrument causes a crash