Due to privacy rules enforced by Apple, Facebook has made changes to the attribution window settings in every account.
Changes in Facebook
The new default attribution window settings in your Facebook account should now be 7-day click for all newly created campaigns, instead of 28-day click and 7-day view.
All your campaigns created before January 28th keep benefiting from their initial attribution settings.
Finally, Facebook is deprecating three attribution window settings previously used: 28-day click, 28-day view, and 7-day view.
As Facebook stated it, "these changes won't impact ad delivery, but the new default attribution setting may result in a decrease in the number of reported conversions."
We recommend you to read the following articles Facebook released in order to better understand the changes made in your account, and how those changes will affect your ads.
Changes in DashThis
When looking at your DashThis reports, all your widgets are modified according to the new changes.
Please note that this only affects widgets with conversion metrics.
Depending on what is set in each of your Facebook Ads campaigns, DashThis affects the right attribution window to the right campaign. Also, if your Facebook Ads account contains an attribution window set at the account level, DashThis will apply this setting since it overrides the campaign settings.
This way, the data in DashThis should reflect the exact same data that you can see in your Facebook Ads account.
Anytime, you can override all settings that are applied as default in your widgets by using the filter "Action Attribution Window" and choosing the one(s) your want.