That is rather common with some bluetooth devices and iOS since version 12. The interaction between ios and the devices seems to miss the transitions from announcement playback to song playback from the Apple music player. It doesn't happen with most speakers but there are quite a few that do have the issue. The work around is to just use an aux adapter at the phone and a long aux cable to the speaker which gets bluetooth out of the equation. Overall, it's a better experience anyway because that avoids the bluetooth latency.
