Most likely the antenna amplifier in the rear spoiler as that's the only shared bit of the DAB & FM receivers - needs fault codes reading and a few other checks to confirm. It could also be the high level brake light, the grounding straps on the liftgate hinges or a few other things - but a DTC read and a few basic checks will narrow things down.
I'd suggest trying a different predictive text engine or deleting all the 'learned' words in yours....