Track:
http://files.tolwyn.com/engine_weirdness2.ntrk
This makes using engine 1/2/3/4 select an impossible issue.
Introduced in 4.11:
DISABLE manual view so you can watch what I'm showing.
Deselect both engines
Show that both are deselected
Select engine 1
Start engine 1
Deslect engine 1
Select engine 2
Start engine 2
Select both engines, bring throttle to idle
This is "normal starting position"
DESELECT engine 1 (conversely, enable only engine 2)
Bring engine 2 to idle
Feather engine 2
Shutdown engine 2
DESELECT engine 2 (we don't need it anymore)
SELECT engine 1
Show that engine 1 is selected (throttle up, then throttle down, etc.)
Bring engine 1 to 70% power; note that all is fine.
SIMPLY DESELECT engine 1 (essentially NO engines are selected at this point)
Watch the RPMs climb in engine 1
Repeat tests. You can easily get engine 1 to fail by simply deselecting it and not changing any other parameters.