i2c Missing on Demo Software

I received a lightning detector as part of a Grove Weather Pi kit. I have wired up the kit per instructions, but it appears the lightning board is not responding to the i2c address query in the both the demo software or the i2c mux query demo software. The board does not show up at i2c address 0x02 using the mux test program on channel 0. I tried to see if the i2c mux was the problem by moving the lightning board to a different bus, but get the sample result - it won't show up on that bus either (or any of them). At the same time, i put other i2c boards on the original i2c Bus where the lightning board was not being detected (Bus0), and they all show up at the proper addresses, so i know the mux is working. I repeated the test on all 4 channels, and all peripherals showed up on all buses.



Are there other things I should try to diagnose this or do I need a replacement?  I am using a RPi 3B+.