http://i.imgur.com/KzpVLXM.png
Blueprint string: https://pastebin.com/NQ7KatGc

In that case (2 different wire connected, but signals only on one of them) max combinator is going to loop diferent signals, and it working totally wrong.
And we cannot use same colored wire connected to max combinator(wich is working correctly) because then not wanted signals will going to the network where there should be only one - the largest signal.

Hmm, I looked into and I'm not exactly sure what's causing this

It will probably be easier to make an explicit input and output for this combinator? Like in vanilla decider combinator. but anyway i already find the "dirty" solution in my current network.