Ficus caulocarpa leaves cannot be mistaken for any other fig in Borneo. The long leaf stalks (petioles) are usually pink to reddish.  This fig tree was fruiting on the summit of Bukit Patoi, Temburong, Brunei when we visited in December 2016.
Ficus caulocarpa Bukit Patoi. The under surface of the leaves shows a distinct hinge or joint where the leaf blade (lamina) joins the leaf stalk (petiole).
Ficus caulocarpa fruit are ramiflorus and grow in clusters along the twigs and branches as with the other  SECTION UROSTIGMA figs in Borneo. Ficus caulocarpa is the most common of  the 5 species of Bornean UROSTIGMA figs.
This Ficus caulocarpa fig tree on the summit of Bukit Patoi in Temburong, Brunei was fruiting when we visited in December 2016.
View from the summit of Bukit Patoi looking north west towards Lawas in Sarawak and the coast.

Bukit Patoi Map

Temburong, Brunei MAP