To put it simply, the next button featured in the bottom left hand corner of the player doesn't work correctly. It seems to work fine for simulcasted things but has utterly failed for me otherwise which leads me to believe that it's behavior is set to do something like select the newest episode chronologically rather than numerically. For example using the "next" button on episode 52 of Sgt. Frog (DUB) brings you to episode 2 of Sgt. Frog (DUB).
I mean that's OK I guess, like episode 2 of Sgt. Frog is still an episode of Sgt Frog... but what happens when you click the next button on episode 4 of Sgt Frog? I mean you'd think you'd get linked to episode 5 right? Or maybe episode 1 of another show... or like at least an episode of SOMETHING right? WRONG!
Seriously try it for yourself:
From this page: http://www.funimation.com/sgt-frog/episode/blood-violence-death-kill/dub
Click the next button which links to: http://www.funimation.com/profile-for-crbean71 (appears to randomly pick a profile)
And you get sent here: http://www.funimation.com/gaming/forum/general-forum/gaming/what-video-games-are-you-currently-playing/60989#comment-88733 (always ends up here though, lol what?)
WtF is that? Anyone? Absolutely unacceptable, fix this ASAP Funimation.
EDIT: Perhaps it's because I'm only on the trial version of the subscription ATM?
Actually, I'm having the same problem. I posted it here about an hour before you. http://www.funimation.com/tech-support/forum/funimationcom/tech-support/when-watching-a-show-next-never-puts-me-to-the-next
Though this confirms it's not just for one show. I also am trying out the free trial as well, so it might have something to do with that.
I'm locking this as a similar thread has been created in Tech Support (and that OP is nicer).