I do not currently use BPCS, though it was used at a previous employment site.
You should be able to use any printable, and especially non-variant, character.
Are you seeing a problem with commas?
Anything you do can cause a problem, depending on what else you do. Commas can cause problems for processes such as reading comma-separated values (.CSV) files when care is not taken.
But the use of normal characters shouldn’t cause problems if all specifications are followed in processing.
That looks like a description field of some sort. Unless you’re using the contents to drive some process, I can’t see how a comma (or multiple commas for that matter) would cause any issues with iSeries programs. If the field is in a .csv file, it will need to be wrapped in quote marks (double-quotes, if memory serves), but shouldn’t be a problem beyond that.