Less Classes than specified when Exporting Index Values and Rates as Polygon

I would like to classify NDVI index map into 10 classes using method Equal Spacing and than export resoults to Polygon Shapefile. Unfortunately after the export I get only 8 classes and empty spaces without any polygon in extremely values. It seems that I always receive two classes less than expected. The check box “Clamped” does not affect on exporting resoults at all.

Resoults in QGIS and settings of a Classification in PIX4D Mapper Index Calculator:

How to export all genereted classes into Shapefile?


I reproduced same 10 zones with equal spacing and got 10 zones on the prescription.
Would you mind uploading your NDVI orthomosaic and shape prescription here Sign in to your account
So I can see what could be wrong.