Cube AI + Yamana MX49 Midi + PC

I record a midi channel from the mx49 and edit it fine in Cubase.
I then add a second midi channel in Cubase and want to record next sound. When I change the sound for channel 2 it also changes for channel 1 already recorded. I did make sure there was no midi input on channel 1 but it still changes.

Also is there a limit using 16 midi channels, so for instance I should not use up several channels for the drum parts only? Like one channel for kick, one for snare etc. Is it correct to use one midi channels for all drum sounds but one channel each in Cubase?

Thank you for any input!