Another thing, I’ve noticed in the schematics that the shield has its own I2C 1k8 pull-up resistors. And the RPI has its own. Combined, the total resistance is too low. May be I will try to switch to I2C0 instead of I2C1, or even disconnect 3V3_RPI (the shield uses two 3V3 lines, 3V3_RPI on pin 1 for pull-up and 3V3_RPI_1 on pin 17 for VDD)