I am experiencing the same. But it seems not be (just) MRA, I have the same at different navigation apps, especially those which have no downloaded or offline maps available. But I am experiencing the same to radio apps as well like Radioplayer, Radio.de or TuneIn. It might be a bug in Apple CarPlay, it might also an issue with the mobile network, not responding in a time fashioned manner, so just on LTE or even slower. I could not really figure out what is causing this.