Hello @scroggyg
I modified my test program to use internal I2C, did a i2c scan w/o ExtIO2 connected and with it - there seems to be no i2c address conflict.
For me ExtIO2 works either connected to port A or to internal. What I noticed though is that I need to wait (after powering up M5Tab5) for the UIFlow2 screen fully being loaded before running the program.
If I do not wait long enough I occasionally see a crash too.
Thanks
Felix