[fallinlight]

I don't know enough about how the iris works to understand what would cause that to happen. A sudden change in brightness seems like the most likely cause. Do observe any sudden brightness pumping when you start a movie from the library?

Unfortunately, I don't recall any other JVC projector owners complaining about a similar issue.

Yes, sometimes the iris clamps down upon starting a film. It appears to be OK thus far today. But the issue does appear to be intermittent/ random.