Facebook Insights notes/limitations

Facebook Reels: At this time, FB reels are not supported.
Historical limitations: Facebook Insights’ API will not retain any data older than 2 years, as stated at the top of their technical documentation here: https://developers.facebook.com/docs/graph-api/reference/v4.0/insights. Therefore, if you go back further than 2 years in the past in your dashboard, your widgets will not show any data.
Page VS post metrics: some metrics can be used both without a dimension ("page"-related metric) or with a dimension ("post"-related metric).
- The metrics for the page may report different data: it will include actions on the page, whether or not it is on a post published during the period you are looking at.

- The metrics for the post will include reactions on a given post and be reported only in the period where the post has been published.
  - ex: 5 likes on a post in June, 4 likes on a post in May (all likes executed during the month of June) will be reported as 9 likes for the page. However, only the June post will show likes as the post in May will be reported for, in May.

Demographic dimensions limitations: Due to the particularity of Facebook Insights’ API, demographic dimensions such as City and Country, will only be returned if there is data for 100 or more people.
Non-video posts, in widgets containing video-related metrics (e.g, Video Views, 30-second Video Views) will display 0 for these metrics. Data for other non-video metrics will be fetched correctly by the widget.
At this time, posts with attachments will be filtered out of the results which may cause some discrepancies.