You may find the glossy honey dew caused by scale insects or aphids, on the leaves. It is sticky and not very nice things when you harvest the leaves and prepare for cooking or other use.
But it is not difficult to take care of it. Just wash the honey dew under running warm water from hot water tap. It will wash the honey dew away, also spider mites if there were some.
The hot water should be just warm enough for bath or shower. Pat the leaves to dry gently after washing.
After drying, glossy honew is gone.