Did the problem start after doing USB firmware upgrades on the T4s with with a restore from a settings backup that was a bit old?
That puts you into a state where IceTV thinks it has sent timers for your recordings, but the timers aren't there because an old set of timers was recovered from the backup.
To avoid the problem, do a settings backup just before you do a firmware upgrade from USB. If you forget, do a Resend all recordings for this device in My Account>My Recorders on your IceTV Web pages. Then do MENU>Setup>IceTV>Fetch EPG and update timers now on the T4 (or other T/U series Beyonwiz). That should get everything back in sync. Doing a reboot or a GUI restart on the T4 will do the same as Fetch EPG and update timers now, but it's less convenient.