Odd watermarking behavior on large photo view

This is something I've never noticed before, although I don't often look at large size photos. In this gallery of mine at least: http://www.winsomeworks.com/Flowers/Spring-Flowers/2726252_yvZve#273398758_sutND if I click on some of the preview photos (such as the one of forget-me-nots in rubble) one of my old watermarks is showing on that large view. Instead, a more recent one should be there-- the same one that shows on all the regular-sized views in the gallery. On many of the photos, the correct & updated watermark is there even on the large view, but on some it's not. I haven't checked other galleries yet. That particular gallery is in a community, in case that makes any difference. Off to check some others now.