Twelve ways a sentence changes what it tells a reader, collected rather than argued. Flip a card to see the mechanism and where in a document it usually happens.
Each card is a pair: what the record said, and what survived. The front is the failure, the back is the mechanism, and the severity bar is how much a reader's next action would change because of it. Nothing here is exotic. Every one of these showed up while reading real pairs of records and summaries, and most of them are invisible unless you put the two texts side by side.
Presented as a gallery rather than a table because these failures are recognisable before they are measurable. A clinician scanning the wall will find the ones they have seen, which is a faster route to agreement about a taxonomy than a rubric is.
Negation and quantity failures cause harm fastest. Hedge and attribution failures cause harm slowly, by eroding the record of who knew what, which is the audit trail question rather than the comprehension one.