This is a plant pathological phenomenon, which is mostly caused by problems in the growing environment of jackfruit, such as excessive rain and weather, low temperature and plant physiological reasons. As a result, the sugar in the fruit cannot be converted in time.
Although the taste of jackfruit may be affected in this case, it can still be eaten. It is suggested to peel off the rust spots on the surface before eating, or choose fruits without rust spots when buying jackfruit.
The above contents are for reference only. If you need more information about jackfruit, it is recommended to consult a professional botanist or agronomist.