Seems like there is some sort of styling bug that if the screen is rotated horizontally, the ticks disappear from the logbook listing:
http://imgur.com/a/bgy1c
It does not affect iPhones, though, so I suppose it's purely due to screen resolution. Tried both Google Chrome and Safari, iPad Air (1st gen) with iOS 9.1 (or whatever is the latest!).
Not a big deal as it still works vertically, but I doubt it's meant to be a feature.