They supplied a new GEN II spider and firmware 1.09 for testing. This was tested on June 24th with very much the same results as the first GEN II unit they sent. Sprints dropping due to cadence sensing failures. Accuracy issues due to offset drift/issues. They've removed the realtime offset display within their app - which was extremely useful in diagnosing issues.
I've given them all the data from this test (along with comparative data from the reference meter). XCadey have asked for more details/video footage/etc. I haven't replied. They have all the detail they need already. I've given them way too many hours/days of my time. This is their issue to resolve, not mine.