The original app center was excellent, they were .. "finessed" so to speak. Then they changed it (like so many websites today most are clunky and they're all terrible, they don't work well, and I'm not just singling out maplesoft) Most websites that are finely tuned are most likely based on old school programming, just recall the old days of mapleprimes - the forum was nicely done - but that's a debate for later. Now to the nitty gritty.
I did a search at maplesoft app center of a particular author, and I know he has at least 20 applications. Only 3 came up, and the last app entry said more apps by this author but it kept disappearing and I kept getting thrown back to application #1 all the meanwhile looking like I'm scrolling further down in the list.
Maybe this is browser issue? I'm using firefox. Maybe Microsoft Edge works better?