you've peaked my curiosity, would it be possible for you to post a video of it leaking back into the container?
Can you actually see the bubbles feed backwards through the clear tube?
I have actually watched the bubbles go through the pump. In both cases, the tubing was pushed up against the clear cover. There seems to be about a 2 milimeter gap between the roller and the cover. I think when the tubing walks over into this gap on the top 2 rollers is when it leaks back through.
No I can't post a video because after it happens the pumps no longer will even pump.
Replacing the tubing has fixed both issues for now. I don't have confidence that this will not happen again in the future. I am thinking that these pumps sat in a warehouse awaiting release and the tubing changed shape. My concern is that the "home" feature will cause permanent distortions and cause the issue to reappear later. A couple of the pumps will be continuously dosing so I am not worried about them. But several will be dosing 10 -100 ml over short periods. I would like to be able to turn "homing" off so it does not deform the tubing in the same spot every time.