Same here. Just like a pattern. And the pattern for me is prevalent when my defense team performs great or horrible.
Just like in this tourney, my defense does not have a loss the first 3 days. I had no losses on the first day on attack also.
On the second day, i lost 2 attacks because of very bad and bad boards. Very bad board for me is when i have a 3-2 team composition but none of my heroes were able to fire their specials until i am defeated and in a very fast tourney at that. Bad board is when my heroes fire once but no favorable tile color as replacements thereafter until i am killed even having 5 to 4 or 3 hero advantage.
On the 3rd day, i usually do not pass through the 3rd flag. Its either 2 consecutive losses or the first and 3rd flags. That is the pattern for me.
A different pattern also is when my defense performs poorly and have a loss or losses on the first day. I almost always reach the 4th day of the tourney.
Nonetheless, I am not saying that there is no real RNG and it is instead based on a pattern but my observed pattern is hard to ignore.