@hehe thanks for sharing your comments, found it very valuable in understanding the assymetric brake system.
we also had a case of flaps being stuck at 40% during landing, using the knob style emergency flap brake valve.
Upon landing and during our ground test, the flaps worked normally.
You mention that you ever experienced internal leakage of brake valves.
Would such a leakage cause the brakes to activate, but yet not "latch" the valve/button and trap pressure?
We suspect that because they were not latched, the hydraulics that activated the brakes in-flight was allowed to return to the utility reservoir when pressure was depleted,
hence the system worked fine during our ground test.