As skoko hints at, if there is an active index on the RW cursor, then a new record will be added to the end of the cursor, but will "appear" to be where ever the index places it. You'll either need to create data that's logically "bigger" than the last record by setting the appropriate value(s) in the field(s) that the index uses, or use SET ORDER TO 0, and show the cursor in it's natural order.
Rick