Thank you Mark for the valuable inputs and screenshots 
If I understand it correctly: it means the I2C on the board isn’t properly working?
(I also tried to communicate with the board with “smbus” instead of “grove.i2c”/“smbus2” and it yields to the same results)
I looked for a workaround based on the datasheet:
It seems we might be able to use UART with this module if we read the datasheet but it seems Rx and Tx are not connected to the connectors if you look at the schematic (Pin4 & 5):
I also wonder about something else:
I actually start to think that opposed to what the Wiki says, it can only be powered with 5V but 3.3V communication compatible. Hence, if powered with 3.3V it might misbehave. (If I have time, I’ll check that tonight with a quick tweak and get back at you after it)
Sorry for this long post.