Based on my observation, 1 cargo source for 2 consumer industries is fine. But once I add the third cargo destination from the same source, there's always one destination that can't get any cargo distributed while everything else is fine.
Which program version?
pak128.german, Simutrans 123.0.1
I can not reproduce:
(https://makie.de/3consum.png)
https://makie.de/3consumer.sve (https://makie.de/3consumer.sve)