The alerts tab shows alerts generated by Burp's tools. This information may be useful to troubleshoot network connection or other problems.
If the same alert is generated more than once in succession, the alerts are consolidated into a single entry in the table, with a counter showing the number of times the alert was generated.
Get help from other users, at the Burp Suite User Forum:
This release contains various enhancements to existing functionality, including improvements to the Spider's link-discovery engine, which now achieves a WIVET score of 50%. There is more work to do in this area, and improved crawling of JavaScript-driven navigation is in the pipeline.
Various bugs have also been fixed.