While trying to collect data from SAL with python I uncovered an issue with the numpy arrays. If you cache the array directly from the data structure (for example, to get an average of the data) you will get bad numbers. The issue appears to relate to garbage collection and the SAL data structure being collected while something else still holds a reference to the numpy arrays contained by that data structure.
Attached is an example python file that has 3 ways of caching the data.
I also tried a change in which I print the min/max of the first data cached while adding more data to the cache. What I found is the min / max of the first set of data cached changes. I have attached an image of it.