HBP: Discrepancy with timeline, help

[Phyllis]

Joywitch:

<<I found a potential Flint in this scene, too.  Trelawney says that 
she saw Snape come in.  That means that she was out of her trance -- 
therefore she had spoken the whole prophecy.  But if Snape was still 
in the vicinity, doesn't that necessarily mean that Snape heard the 
WHOLE prophecy?  We know that the person who told Voldie only heard 
half of it.  There's 2 explanations I can think of <snip> >>

I can think of a third.  Trelawney wouldn't want word to get out that 
she can't remember what happens during certain periods of time.  She 
must have been in the trance for the entire prophecy - Harry 
witnessed her making the 2nd real prophecy, and when she "woke up," 
she couldn't remember any of it.  In HBP, Dumbledore tells Harry that 
Trelawney doesn't appreciate how great her danger is because she 
doesn't know she made the prophecy.  So I don't think she ever came 
out of the trance (at least, until the prophecy was completed).  I 
think someone told Trelawney that Snape had been crouching at the 
keyhole, and over the years, Trelawney has either started to believe 
that she actually witnessed it, or has concocted the story she told 
Harry so she doesn't have to admit she didn't witness the events 
first hand.

~Phyllis