1) Having your rule stop working randomly sounds a bit strange and I can't think of anything of the top of my head that would cause that. Can you provide some more details around that?
What do you mean by the rule not working? Is it not firing anymore or are you not seeing a beacon or are values in the beacon incorrect?
URL and rule name?
Are you publishing the rule to production or working in a staging environment?
2) The Core extension is installed by default in all new web properties. This is to help customers with basic event detection and conditional logic. Are you able to actually build the library or does your experience match this post - Launch Bug - Unable to Save and Build Library
3) Errors in our in product code editor are suggestions rather than actual errors most of the time. Here is a poll that I think might explain what I assume is happening in your case.
If we want to dive deeper into one of these issues, please open another question on the community about the specific issue with all the details. That way we can keep the thread clean about a single issue. Since this thread was started asking how to report bugs in Launch, I'd like to branch each of these off into their own threads if needed to work toward a solution. Alternatively, If you'd prefer a more private 1:1 troubleshooting experience, you can also contact customer care to go over these issues.
I have few of them actually. We have been noticing that some of the rules will be working fine and then stops with no reason. To fix the issue, we create an identical rule and delete (or disable) the original one.
This also can be noticeable when creating new web property, as the "Core" extension will be installed by default, you will notice that your 1st dev build will never work and keep failing until you disable the Core extension, build, and then re-enable it.
Finally, when the debugger show an error/alert in the code, it display the error/alert description behind the code editor (in the action section) as it show in the following screen shot, so you won't be able to see the actual error/alert description
You're welcome to post about them here on the forums as you've done if you'd like. You can also contact our Client Care group to open a ticket. If we are able to verify the bug and are unable to provide a solution, our Client Care team will open a bug with our engineering department.
Out of curiosity, what issue/problem were you having and are you still experiencing it?