If you are analyzing your boosted posts, there are situations where you might see boosted results under the Post Summary table but not under the Post Insights table.
The Post Summary table shows the results of posts published and posts boosted during the selected date range. The Post Insights table shows the posts published during the selected date range, regardless of when they were boosted. This is why you might see posts that have had a $ spend on them, even though the results of that boost are not included in the summary table.
Let’s say you published a post on July 1 and boosted it from August 1 to August 5. To see the overall results of the boosted post under the Post Summary table, the date range should include August 1 to August 5, when the post was boosted. To see the specific boosted post under the Post Insights table, the date range you select should include July 1, when the original post was published.