Hi Jason,
No, segmentation violations should never happen under normal working conditions. That said, memory access errors do happen occasionally on all platforms, as a result of a variety of reasons, most of them hardware- and/or configuration-dependent, and in most cases machine-specific and difficult to identify.
The problem here is reproducibility. If you can find a repeatable sequence of operations, or a given working context, where the problem can be reproduced consistently, then it is obviously a bug and we can work to find, understand, and eventually fix it.
There have been no reports about segfaults associated with repeatable patterns on OS X or other platforms with the latest version. Are you using version 1.8.4.1195 of PixInsight on OS X, or an older version? Can you tell us something that could help us reproduce the problem?
