It is not Arhopala avanthina but something equally interesting.
The diagnostic ID for A. avanthina is that the FW basal cellspot is absent.
In the image all three cellspots are present. ie. one at cellend, one at mid cell & the 3rd basal (actual position is sub-basal).
Arhopala kurzi have 1. all three cellspots present, 2. HW postdiscal band widely dislocated at vein 2, & 3. FW postdiscal spot 3 (ie. in space 3) elongate towards base (variable).
All three criteria are met here. https://singapore.biodiversity.onlin...doptera-000440