As per POWO, Colchicum coloratum subsp. burchellii is a synonym of Colchicum burchellii: https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:77083471-1

Also see: Manning, J.C. 2023. ‘A nomenclatural correction in Colchicum L. (Colchicaceae: Colchiceae) in southern Africa: two new combinations for C. coloratum J.C. Manning & Vinn., nom. superfl.’. Bothalia 53(1): a5. http://dx.doi.org/10.38201/btha.abc.v53.i1.5