I know you have a source that says that if you believe something is true and its turns out to be false it is a lie.
I reject that. Here is what I conisder the correct definition of lying....
lie 2 (l
)
n.
1. A false statement deliberately presented as being true; a falsehood.
2. Something meant to deceive or give a wrong impression.
v. lied,
ly·ing (l

ng),
lies
v.intr.
1. To present false information with the intention of deceiving.
2. To convey a false image or impression: Appearances often lie.
v.tr.
I think most of us agree that if you believe something to be true, and it is later found to be incorrect that you have not lied, you were wrong.
I think most of us agree that lying is a concious act.
So ironically you would think that I am calling you a liar.