F.3:2 - Problem Frame

Source-local lexical notes often over- or under-differentiate meaning:

1. Over-split: an abbreviation and its full form are treated as different meanings despite interchangeable source use.
2. Under-split: one gloss covers incompatible argument patterns or conclusions.
3. Source drift: different chapters, editions, or translations are blended without checking whether the interpretation basis changed.
4. Didactic drift: the Tech and Plain labels begin to teach different things.

F.3 repairs this by testing usage under the exact source basis rather than by counting strings.