The condition was changed to use self.streamed_span for the not-None check, but the isinstance(self.span, NoOpStreamedSpan) check still references self.span. The self.span property returns None whenever self._span is a StreamedSpan (including NoOpStreamedSpan), because its getter filters by isinstance(self._span, Span). Since isinstance(None, NoOpStreamedSpan) is always False, the guard never short-circuits, so when a NoOpStreamedSpan is active the code falls through to self.streamed_span._to_traceparent() instead of using the propagation context. This produces incorrect traceparent headers for unsampled/no-op spans, breaking distributed tracing fidelity.

Also found at:

• sentry_sdk/scope.py:605-607

The guard not isinstance(self.span, NoOpStreamedSpan) mixes two mutually-exclusive properties. The span property returns self._span only when it's a Span (line 884), while streamed_span returns self._span only when it's a StreamedSpan (line 901). When self.streamed_span is not None, self._span is a StreamedSpan, so self.span returns None, and isinstance(None, NoOpStreamedSpan) is always False. The guard never trips, so _to_traceparent() will be invoked on a NoOpStreamedSpan (which is a subclass of StreamedSpan, traces.py:556), producing incorrect traceparent headers in no-op tracing scenarios.

Also found at:

• sentry_sdk/scope.py:605-607