Struggling with 1.2" 7 Segment with multiple devices

[TheWishy]

Oddly, if i connect to a different ground pin on the Pi, the display detects and the code executes, but only the decimal point illuminates on the display. Reproducible against two different displays. Tested with a multimeter, read 3.3v, so definitely had a ground pin.

Also worth noting that the jump leads are still attached together, so SDA and SCA are both next to eachother. Potential route for interference?

Edit: Massive progress. Hooked up IO to 5v and now it's working correctly

[adafruit_support_bill]

Not sure what is going on with the decimal point. Interference between SDA & SCL is not usually an issue. More often you will have problems with external noise pickup, or ground-bounce due to fluctuating loads.

And yes, 5v will tolerate long runs better than 3.3v.