If you are referring to writing from right to left, that is normal and in line with the traditional Chinese brush writing habit.
If you are referring to mirror-image reverse writing, that is abnormal and is a mistake made by the manufacturer when doing design. Nowadays, design and engraving are all done by computers, so at a certain link, a mistake operation will cause this result. (For example, if you accidentally select seal engraving when selecting engraving mode, the system will automatically mirror the pattern)