I’ve not seen this before. Can you set it to use one vsa100 chip and try again? It’s in the driver settings.

Games and benchmarks seem to work fine in single-chip mode. It's only when using both chips that the fault occurs.

The card has a slight warp where it's drooped due to gravity in an upright chassis. Maybe there's a cracked solder ball under one of the BGA chips?

Is the primary VSA-100 chip on the left or the right?

The seller would not negotiate a partial refund, so I ended up returning this card instead of attempting a repair. It's a pity, because I really wanted to fix it. However, accepting the risk and cost of repair on top of what I paid for it with what was supposed to be a working card is untenable.

That is a shame, but it is the right thing to do, although with all retro hardware it does die. But if you purchased working, then it should be working.