1. wrt changes done in PR - https://github.com/openshift/console/pull/13676 TaskRuns are fetched for Failed and Cancelled PipelineRuns. 

In order to still improve the performance of PLR list page, use pipelinerun.status.conditions.message  for Failed TaskRuns as well and along with that, for any PLR, if string pipelinerun.status.conditions.message having data about Tasks status use that string only instead of fetching TaskRuns 

ex string : 'Tasks Completed: 2 (Failed: 1, Cancelled 0), Skipped: 1'

2. For Failed PLR, to show the log snippet, make the API call on click of Failed status column in the list page