I am using the Lighthouse API to get page load metrics for my site. I'm getting some huge outliers for my Total Blocking Time (TBT) metrics.
Since the results are a little different with each request, I'm taking the average of 5, so I'm making 5 requests per URL I'm testing.
All other metrics differ slightly with each request, except for TBT. Usually it ranges from 0 to about 80, but then sometimes it comes back appx 800. See screenshot below, where TBT is third column of data, and the rows are 5 requests for one URL. The last row is the average.