DocumentEncodeError

The document holds state A12 Document JSON has no shape for, so encoding would silently lose it. The one reachable case is a non-repeatable group row above 1: A12's reader accepts an array at any group (so such a row stays readable, and formal validation reports it), while A12's writer emits a non-repeatable group as a single object. pointer is the canonical A12 pointer of the offending row.