Yep, I know about that one... It happens when increase the delay on a Delay pipe. Decreasing it works correctly.

I have a new version in the works with this bug and others fixed, pre 10.4 compatibility (I forget how far back it goes now, but certainly 10.3.9), and many other enhancements. I'll try to remember to release a minor update before I dive in and start on the major one. Long-term, I plan to overhaul the graphics, change the UI around a bit, add a front end, add sounds and background music, and build many more levels. I want to see a project through to the very end for once.

Thanks for the report.