So far we haven't detected any lot dependency, which isn't to say that some lots are not pod-error prone, just that the reports come from a variety of different lots.
The errors are not occlusions, which are signaled by the PDM as occlusions. Those still occur for some people (I've never seen one). Rather they are "PDM error" errors.
There seems to be no consistency in the error codes, at least nothing I have been able to determine so far (but then I don't know how to decode the codes and haven't analyzed my recent failures.)
In my case the PDM errors started immediately after the change to the new pods - the first four failed - however the failures were taking longer and longer (indeed, pod 3 lasted 71.8 hours.) It seemed that the PDM was learning from the failures and programming the subsequent pods differently.
Since then I've had a total of 11 PDM errors out of 42 pods, however failures have got less and less frequent.
The failures occur both during bolus and basal delivery. Bolus failures occur at the end of the bolus. This probably just reflects when the pod does its checks.
My failures are site specific. After the first four failures (which occurred in sequence on all four sites I was using) all the failures occurred on my upper arms.
After some experiment I discovered that, with I think one exception, the arm failures only occurred if the cannula was high on my arm. If I position the cannula more toward the center of my triceps muscle I avoid the failures, if the cannula is at the top of the triceps, towards where the deltoid muscle crosses it, I get failures.
I suspect the new pods are far more sensitive to site issues than the old ones and putting the pods where two arm muscles cross is just too much for the heightened sensitivity. I still suspect there is also some patient-specific adaptation in the new system as well.
Now I use six sites - over the triceps, the upper center of the pectoral muscles and lower back. I seem to be getting near 100% success with these sites, so long as I am very careful with the upper arm position.