With the high temperatures we are experiencing at the moment be aware, leaf burn can occur on frangipani's. This is usually due to watering of the leaves during the intense heat in the middle of the day. If you’re foliage watering do so in the morning or late afternoon.
If your tree develops thin narrow yellowy leaves, it can be due to herbicide damage from sprays such as ‘glysophyate/round up’. Ensure to avoid spraying too close to the tree or on windy days.