There are numerous posts about this on the forum.
This should happen with repeaters no matter the layout when sub fields are hidden by conditional logic. It has to do with fields that are hidden by conditional logic are not submitted or updated. Stray values in the database will be retained by the row index from when they were not hidden by conditional logic.
Here is one of the many old posts on this topic https://support.advancedcustomfields.com/forums/topic/acf-repeater-sub-fields-are-losing-swapping-content-when-re-ordered/
