I recently had to patch up a schema that was defined but had to be evaluated for re-usability.
This warning was generated:
Warning 1 Record "RecepientOrderShipDetail" - The tag overlaps one or more fields that contain a fixed data value. \OrderShipped_FF_<System>.xsd
The record RecepientOrderShipDetail had a TAG identifier which was correct, however for some reason a child atrribute @RecordID has a FIXED value with the same value as the parents TAG identifier.
Since both the TAGS were working on the same Offset the positional ‘bandwidth’ was used by the Attribute.
To prevent this warning I removed the fixed value of the Attribute
Since this error is rather unclear I hope this helps in solving the problem when you run into this.