Thanks, that is logical indeed.
It is still a great meter, I just need to remember that just about every piece of test equipment will have its own 'features', and some that only appear in rare or unusual circumstances. In this case, I need to remember not to panic when an unexpected value appears on the display, and when it does, to do other tests to work out if it is a true reading or not. And as a general principle, to make sure that I interpret readings appropriately, doing a sense check as it were.
In an ideal world, an intelligent meter could do rules-based checking before displaying the result, e.g. to assess Crest max as zero if the current is zero. It could be included in the processing rules of an intelligent meter, but processing rules can sometimes get things wrong too (like the cat photo being confused by Google's AI system into appearing more like guacamole), and then a good intelligent meter (if such a thing exists) would probably cost a whole lot more than a 867s.