Sorry, Stuart, I express myself badly. I have never seen anomalies on both systems at the same time. They seem to be random on both systems. E.g., this morning's glitch was only on the Davis system, but one I did not report here yesterday was only on the WH system, as some above. They happen at totally random times, day and night (except for Brian's suppressing night time ones on WH).
I've not done any software development for well over 20 years, so have forgotten more than I ever knew, but my guess would be loss of sync over the 100 bytes transfer. Just one extra or missing bit would do the job. If it happened once at random, that is easily understood: less easy for my feeble brain is the same thing happening over many minutes.
I think that's what is flummoxing all of us, how do you get such wrong but sometimes consistent errors over a few minutes, which is why we are clutching at straws. I suspect Brian is correct over the WH system. The Davis system is a different kettle of Surströmming, and strange that you seem to be the only person reporting this.