It says:
41 tests failed:
...... too many results, data snipped.... ( Code Search )
external/wpt/2dcontext/the-canvas-state/canvas_state_restore_001.htm ( Code Search )
external/wpt/credential-management/federatedcredential-framed-get.sub.https.html ( Code Search )
external/wpt/credential-management/passwordcredential-framed-get.sub.https.html ( Code Search )
external/wpt/css/css-color/t32-opacity-offscreen-b.xht ( Code Search )
external/wpt/css/css-color/t32-opacity-offscreen-with-alpha-c.xht ( Code Search )
...


looking at the failures e.g. https://ci.chromium.org/buildbot/chromium.webkit/WebKit%20Mac10.10/45043 it is clearly:

 
Unexpected Failures:
* bluetooth/requestDevice/chooser/new-scan-device-added.html

and not a new instance of some random other layout test failure.

For this occurrence there were multiple alerts firing for new and old bots with mismatching descriptions, yet there was one new cause to be linked.

Could not convince sheriff-o-matic to separae the instances and group the related failures to manage them.