State a renderer infers from history must reset at every discontinuity

A summary renderer inferred 'this value is a clean 0/1' from an earlier bucket and carried that forward through buckets with no reported change. The data source had a discontinuity: it restarts with a value that by design is not reported as a change, and that value could be unknown (x). The carried inference survived the restart, so the renderer drew a confident 0 line where the exact renderer drew x. Any state you infer from earlier data (known value, last level, monotonic run) should reset at every point where the source can jump without reporting a change. Test with a jump to a different kind of value, not just a different number.