Hello and welcome to FF ! Although White's do burrow at times; it can be a sign of a problem or stress. Please read this article and review you are providing for all it's needs: Frog Forum - White's Tree Frog Care - Litoria caerulea. Whites do require good ventilation and your humidity sounds a bit high for a well ventilated enclosure. Don't think high heat is the issue; they require a 85F basking spot with 80F overall.