Yes I have this proboem with the first Rollinia I planted. The issue for my tree is the heavy soil and also tree was planted too low. Everytime it rain dirt would wash down into the hole further burying the roots that were already in heavy soil with compost that had not properly been mixed with native sand/soils. The tree has become very chlorotic with yellow frail leaves.
Not sure how your tree was planted but maybe the roots are unhappy. How thick is mulching?