FOR and relative
FIND statements reposition all open index cursors for the same buffer. (For more information, see
FIND repositioning.) However, in order to reposition a buffer's index cursors, the AVM must have all the index fields available in the buffer. If you fetch a field list that excludes some of these fields, the AVM marks the relevant indexes as being incorrectly positioned.
This does not matter for the query or fetch loop that uses the field list, because the AVM might never reference the relevant indexes. However, if you later execute a FIND NEXT or FIND PREV using one of the badly positioned indexes, the AVM raises the ERROR condition and the FIND fails.
To avoid this error, always specify the fields in your field lists that participate in the indexes that you reference.