Although King & King (1984) classifies Dumpas as Paitanic, Lobel (2013:396-398) classifies Dumpas as a Dusunic language that is particularly closely related to Sungai Karamuak (also called Sukang), but has been heavily influenced by neighboring Paitanic languages.
King, Julie K., and John Wayne King. 1984. Languages of Sabah: A survey report. C-78. Canberra: Pacific Linguistics, The Australian National University.