Uhhh last time I checked Tapas was just a swipe to the right. Most of the stuff on the MangaRock app is read right to left (i use it too lol), maaaaybe you're trying to swipe it left without realizing
? You shouldn't have to be doing the weird twisting stuff you're describing here xD If you can't get it to work, just hit back and load up the next episode from the episode list.
And no, it's not infinite scroll like Webtoons, unless the comic itself is built for that. For example, Fisheye Placebo is a vertical comic that reads downwards, so obviously scrolling down works there. But HJ-Story is just single panels so yeah, infinite scroll would be kind of pointless. Webtoons is all about infinite scroller stories, Tapastic is more about bite-sized episodes of gag comics and such. They're different markets so of course they're gonna be built slightly differently.