As far as I can confirm, the bot gets flaky at least from #26777 (Mar 28 09:03 PST) to #26970 (Apr 09 19:50 PST).
https://uberchromegw.corp.google.com/i/chromium.memory/builders/Linux%20Chromium%20OS%20ASan%20LSan%20Tests%20%281%29?numbuilds=200

I've tried to investigate it but I couldn't find any causes of it. Let me file a bug to track the issue.

I'm suspecting that something in mus_browser_tests is buggy, but added a "Infra" flag for sure since it sometimes fails by "exception" state occasionally.