Hi Da,
Have tried to replicate in same build of 12.6 as yours. Unable to get same result!!!!
The only thing I can suggest is to check if there are declarations somewhere else of a variable of the same the same name... You could also have ib_true and in your code typed Ib_true (1) not lb_true (2)..(first is an uppercase i and second is a lower case l impossibIe to see the difference)
But to answer your OR question: Yes! forget the local variables, they are not needed. lb_true?
hth
Lars