I've been playing with mixed fluid design since 0.18.32 (including unmixer viewtopic.php?f=6&t=86007)
quite a lot of issue I found : one due to rounding (the suggestion one), the second is the inabilty for a pump to push the last drop of liquid
The fluid is not completely pushed out of the pump, Jamming my system!
As you can see, the next pipe is empty, and the next pump is waiting to pull the fluid!
![Image](https://forums.factorio.com/images/ext/e9bf0c814edaaf3c78cb4c11f56377e0.png)
Mpmpmpmp