Wanted: who knows this Paphiopedilum?

Olaf Gruss published an article about a very dark Paphiopedilum in issue 4 of 2022 of the Orchideenjournal. Here is a short excerpt from the article with a photo of the flowers:

Almost 20 years ago, an orchid lover was shown two previously unknown flowers of a Paphiopedilum at a plant market in Hanoi (Vietnam). The flowers were quite small, but already opened. They had obviously opened by themselves, no help had been given by hand. The collector/dealer did not want to sell a small plant. The seller could not say whether this very dark, almost black lady's slipper orchid was collected in Vietnam or the neighboring countries.

A short time later I also saw the picture with the two flowers on the collector's hand - but then forgot about it again. The above article in the Orchideenjournal now awakens these old memories in me.

Somehow the orchid world had hoped at the time that plants from it would appear later - however, in Europe one has never heard of it or seen more plants/flowers from it.

I would now like to try to search for this plant in this way:

who has seen this plant before or knows in which country this orchid grows?

I would be happy to receive more pictures and more information about this plant.