When configuring pop-ups for a feature class in ArcGIS Pro 2.7.6, 2.8, and 2.8.3, edits made to the order of fields are preserved only in the Configure Pop-Ups window but not when there is interaction with the feature class.
After unchecking the 'Only use visible fields and Arcade expressions' checkbox and committing to the pop-up changes, the fields info in the pop-up is separated from the table, and reordering fields in the table will not affect the field order in the pop-up configuration. It is expected that the order of fields in the Pop-up Configuration pane is different from table in this case.
Regarding field order pop-up content does not match field order in popup configuration page. This issue is no longer reproducible in ArcGIS Pro 3.0+. It is recommended to update to the latest version of ArcGIS Pro.
解决办法
Rearrange the fields in the Configure Pop-ups pane.
Uncheck the 'Only use visible fields and Arcade expressions' check box.