I suspect that's not true. Surely you had good idea about it or you would not say 1337 is displayed as leet. You would not see the number 1337 and only seeing the word leet you would not be able to guess your post count.
And this was (OP) your 1338th post, right after the leet post.
Maybe he did remember his previous post count before he made that post which caused 'leet' appearance. Now leet has gone, but OP can get it back if he delete some past post to bring his total postcount back to 1337. Just a small tip, and kidding for the weekend.
Now, it's time to lock your thread, OP.