Very normal for many species
A few searches here will produce many prior threads about this. Many websites talk about it as well. It is not a matter of how many crickets or other insects are available. While we are not sure of all the needs that are addressed by chameleons eating various types of live plants and roughage, there is little doubt that it is an instinctive and common behavior, and serves vital needs. When observed in the quantity that a little research will show, such behaviors are to be accepted as normal, and then provided for as best you are able, and not seen as something wrong and in need of correction. Hope all goes well.