What rating cut out fuse have you got? The charger thinks it’s 60A so when other high power devices are on assuming it can get an accurate ct clamp reading it’ll reduce the car charger so you don’t blow the fuse.
If your fuse is higher set the rating higher. Also check how the ct clamp is fitted. I had sparked in replaced tails and they put the clamp on backwards so much for employing qualified sparks.