Correct.
If you are tuned to a network where another related station does travel news (eg tuned to Radio 1, but a local BBC station has travel news), the radio will jump to that station to let you hear the traffic. IF this function is on (it says TA -- for traffic announcement -- on the display) but its not a strong enough signal (it stops showing TI -- traffic info supported by this station) then it beeps. (Typically if you drive into a tunnel or over hills into the next valley)
To turn off travel news, tune to station you want to listen to, then press TA button (original Multi radio - its a very small round button in a top corner) so that 'TA' is not showing.
If you DO want it on, but when news cuts in you don't need to here, press TA to go straight back to your station...
IF you persist and find the menu settings, there's an option to turn the 'beep' off