I2C busses mixed up?

Hello Learned group,

I have an I2C problem that I confuses me: I have activated I2C1 in uEnv.txt. That works. Now i2cdetect -y -r i (for i = 0,1,2) gives a quick response. However, i2c2 behaves like i2c1. i=1 shows nothing connected, 0 shows some UU’s and 2 shows devices I can recognise: I can see the addresses for the rtc and the motor cape. These are designed to work with i2c1, so the rtc and motor cape do not work.
What happens here and how can I resolve that?
Many thanks in advance,