3.3V I2C SDA/SCL but 1.8V VDD?
Yes, you will almost certainly run into problems. From your datasheet:



A spec like this most likely indicates the presence of ESD protection diodes on the SCL and SDA lines, connecting them to the power and ground rails.

If you power this with 1.8 V, and connect SCL (for example) through a pull-up resistor to 3.3 V, it will pull the SCL line down to about 2.5 V. This could cause problems with other chip recognizing a high voltage on SCL. The extra current from SCL into the VDDIO supply could cause other unexpected (and unpredictable) behavior.

It may be possible to operate your sensor with VDDIO at 3.3 V while the main VDD is at 1.8 V. I don't see anything to prevent it listed in the characteristics tables, but I didn't read the complete datasheet to be sure.