Steps to Reproduce

http://zkfiddle.org/sample/38lo22l/2-shadow-bug

Run fiddle
In the first set:
Click toggle val1 4 times
then
Click toggle val2

on the second set
click toggle val1 4 times
then
Click toggle val2

Current Result

In the first set:
the if shadow element EL expression toggles for the first instance of it being set to true.
If it is set to false, then true again, the if statement will not trigger

In the second set:
the first member of the expression can be used to make the expression true after the first time, but other members act as in the first statement

Expected Result

If any member of the expression cause it to become true, then the if shadow should trigger

Debug Info

binding expression members order matters in this bug
if the expression is:
(val1 or val2) and (other)
val1 can still trigger the if shadow element but val2 can't

if the expression is:
(val2 or val1) and (other)
val2 can still trigger the if shadow element but val1 can't

Root Cause

Workaround