Multiple Pmaps Price Hover Goes Away?

So, I have this memory that if a pricetype has two pmaps, even if the dates have no overlap, when you go to the house view and hover over a seat, it won't display a price. That area will just be blank. I also thought the same rule applied to the Prices tab of Performance Details.

But I'm finding in practice that sometimes the hover still displays the price and sometimes it doesn't, and so far I can't figure out what the difference is between the perfs in question. Both have two pmaps. Neither have overlapping dates. It also seems like I was wrong about the Pricing tab and that shows whatever price is valid the moment you're looking at it? Can anybody set me straight?