See Flow history after data has changed
When you click a record in the Flow History pane and data for that record is available, you get a special view of the cards that shows the actual values that were used for that particular execution of the Flow.
However, if the Flow has changed since that the time of that execution, some or all of the values may no longer show up correctly:
If cards or fields are added, they will show no values.
If any cards were moved, the values will show up in the new position.
Values that correspond to fields or cards that were deleted are not shown.