Playback was fine but now pauses for 1/2 second every 40 secs, or so & then resumes

[ohjustuse]

Plan

Free

Country

UK

Device

(iPhone SE

Operating System

(iOS 13.3) Bose stereo in the car.

My Question or Issue

This problem only happens in my car. It does it with BT and when connected by wire.

I've deleted/reinstalled BT connections on both phone and car several times. Disconnected the car battery to reset the stereo.

Deleted/reinstalled Spotify app & signed out/in of everywhere

Have reset network settings on the phone. Have done a complete reinstall of the phone. Still the same.

Playback on the phone is fine.

Any suggestions please?