I think I recall seeing a suggested workaround for a periodic resetting of the time. It was either on this site or the Acurite site. If you haven't tried it already maybe that will resolve your problem.
I've suggested that a few times, but I finally had the problem myself and I don't really think that is going to help (though it doesn't hurt to try). I'm thinking the clock drift might be more of a symptom than the root cause.
Last week I had an Access unit that went "offline" and stayed that way. It had been running fine since it was installed a few months ago.
I took a look at the traffic during this time and saw that all traffic to myAcurite had stopped... there was nothing on port 443 at all. However, traffic on port 80 to wunderground continued without issue.
Just to make things really weird, I couldn't clear this behavior with a simple power-cycle. I had to remove all power and batteries for about 5 minutes, then power up again.
After doing that, traffic to myAcurite started up again.
I'm stumped as to what the trigger might be. It's really weird that only traffic to myAcurite is impacted. Or maybe it's only encrypted traffic that's impacted.
The Access has been running fine ever since, but I'm sending it back to Acurite for analysis, anyway.