Flat balancer ignores priority when lift connected

Issue description

Flat balancer ignores sulfur priority input when lift with coal is directly connected to balancer.

Reproduction steps

1. Load attached save.
2. Observe rubber making production. It seems to be random recipie either sulfur or coal.
3. None of lifts or conveyors (coal or sulfur) connected to balancer isn't animating. Load of materials into rubber making plant is instant.
4. Prior to savefile it was only coal. After truck imported sulfur it's only sulfur but still bugged conveyors & load times are int the savefile.

Game version and build number

v.0.6.2a (b328)

Operating system

Windows

Attachments

balancer-lift-bug.save

I attach another save with side effect. I paused conveyor and lift with coal. Rubber makers is still instantly loaded with coal coming endlessly from bugged conveyor between rubber maker and balancer?
lift bug 2.save

Maybe initial issue title is misleading and source of problem is not in a balancer itself?

Firstly, it's U-shape Balancer, secondly, it doesn't work that way, there should be only one type of resource.