Ok thank you. Just wanted permission before I started poking.
So I removed that Retail Portal Pi from the web dashboard and now I can see your remaining device (Lele Pi) on my Android app.
That’s odd that it worked before, but I suspect this incompatibility is at least what gave flaky results even if it worked some of the time.
If it’s not too big a pain, I would recommend backing up any important data and trying a fresh install of the current Raspbian builds, Jessie or Jessie Lite, on the Pi, then re-adding it to your Cayenne account. I suspect the mobile app will be able to see it in that case.
You can download Raspbian Jessie or Jessie Lite here: https://www.raspberrypi.org/downloads/raspbian/