I'd cover it with moss. The soil in the plant may have fertilizer or other toxins.
My one male did this when He first arrived here and I posted a thread asking about it .
The answer was mostly they were looking for minerals from the soil that they lacked.
He appeared very healthy and I do gutload and dust food items. But I did not use a multi vitamin at that time. So I went out right away and got a good mulit vit powder for chameleons . And covered the soil. He has not done it since and he is 4 months old now.
His photo is my avatar so you can see he's quite healthy