Based on information from Chris and the Particle team provided about Argon and Boron have different I2C setups on the feather boards. All nRF52840 MCU Gen 3 devices have 13K ohm pull up resistors on. SDA nd SCL.
The solution to getting data at all was removing the two 2.1K ohm resistors on the ADM00686 (MCP39f521) development kit. For Argon I used the 13K ohm internal pull-ups plus external 2.4K ohm resistors to achieve a 2.0K ohm equivalent pull up on the I2C bus.
For Boron, I just used the 13K pullups in the nRF52840 and the 4.7K already on the board because the Boron has a few I2C devices on it already.
This didn’t fix my issues completely, now I can get data that is accurate to my test instrumentation but the I2C bus still drops out from time to time, about every 8 to 24 seconds. I’m looking into these issues in more detail.