5.1.2 speed change on audio broken

I drop a clip into a workline, Apple J and change the speed to 150%. I let a little bit of this render, test it, and decide it's not fast enough. Then I select the clip again, change the speed to 200%. The rendered bit does not change to show that it needs rerendering.

I render what's left to render and play it. The first part of the clip that didn't need a rerender plays at 150%, the second part, which I just rendered, plays at 200%. The workaround I'm using is to set the reverse button to force unrender, then reset to the correct settings, and re render.

This appears to only affect audio, but I think I may have had an issue with video recently. I didn't stop to think about it at the time, just worked around it.

Andy Neil says video works fine on his system, but has this to say about audio :

On testing the audio, I can confirm that I had the same problem that you did. Stopping the render halfway and changing the speed of the clip to 200 does NOT force a re-render. And when you render the faster speed, the originally rendered audio remains at 150. I'd say that's definitely a bug.

I can't confirm that it happened on video too.