It is highly probable that Prosotas pia pia occur in Singapore.
Here is another male from Singapore.
On the HW the dark marginal line angled out in a 'V' at vein 2 (just below the black spot) indicating where the tail is broken off.
The submarginal & marginal spots are much faded. https://inaturalist-open-data.s3.ama...jpg?1631959024