Could be, I did note a suggestion to set up an account in advance of it becomming required last time I viewed Iplayer content via my browser.Perhaps the new requirement to have a iplayer account and sign in is creeping in ?
Looks like BBC 3 TV has moved, again, see attached screenshot. All the other catagories I use Live, Most Popular and A-Z are working fine.
Update the site in the usual way and give it a try.