That's a cross of exul and a background of insigne sanderae... I did buy some in the 2000's as well in Thailand... until I found that it was breed by Doi Tung, totally unaware that it was used as a 'species' by unscrupulous local sellers.
Doi Tung did cross exul with several insigne sanderae, Actaeus, San Actaeus, Dorama, etc... as they wanted to breed complex Paphiopedilum that can grow and bloom in the lowlands, specifically Bangkok, where they were selling a lot of plants at JJ Market. This part of the story I know since not so long actually...
Out of their attempts came those 'exul var. alba' 'exul var. sanderae' ' exul var. aureum'... and a few gratrixianum on steroids too