The Kefrens bars effect is the part of 8088 MPH that is most sensitive to the instructions being a cycle faster or slower here or there. The MCL86 doesn't claim to have perfect emulation of timing, so I would not necessarily expect this effect to work reliably on it.
The artifact colours are quite off as well, so I suspect the card used was not a real IBM CGA card.
On my ATi Small Wonder and Paradise PVC4 cards, I get the exact same Kefrens bars, with the top chopped off.
Having said that, the fact that the music slows down noticeable during the moire-effect seems to indicate that indeed some instructions are a few cycles off here and there.
