p.decimator waveform display selection affects rate

I'm having an issue with my slightly customized patch based on p.decimator (which uses 2d.wave~ at its core). Download the zip and open decimator.maxpat. Click Replace to load a sample into the buffer.

It behaves as expected until you use the waveform display to select portions of the buffer. If you select the entire sample, it works fine. If you select some portion of the sample the rate of playback changes. And if you select some portion beyond about the midway point, you will hear nothing.

Is this something that can be overcome with the current implementation?

Thanks for any help!