Might he be identical with 'Phags pa's disciple བཙུན་པ་སྟོན་གཞོན། (~13th-early 14th cent.)?
He seems to appear in the lineage of the Hevajra root tantra (བརྟག་གཉིས), see Ngor chen's record of teachings received; ngor chen thob yig [1993] (p. 355.1), here སློབ་དཔོན་སྟོན་གཞོན. For the same lineage, see lnga pa chen po'i gsung 'bum [1991] (vol. 4, f. 313b), here སློབ་དཔོན་གཞོན་སྟོན
tiblib ཨང་རྟགས།: AETP2815