Yeah - I just got another T. I do have an A but it does occasionally error out. I got around this by putting it on a smart plug and turning it off for 5 minutes every 6 hours. That way if I am away from home the longest the tank will ever be without heat is 6 hours, annoyingly you can't reset them remotely with the app - which I have now uninstalled.
Replaced because one of mine needed re-calibration - by 3C! From past experience that's an indicator that the probe is on its way out. Fine while the error is consistent but then one day it starts jumping around at random, so better safe than sorry.