We literally have had twenty four Thinkers in a row.
Let's think about this for a minute. If we're assuming that the midbosses have an equal chance of spawning, this is nearly a statistical impossibility.
The chances of getting 24 Thinkers in a row, assuming the ~33% chance, is 1 in 359 billion. I'm just trying to figure out if you're mistaken, something weird is going on, or you just won the worst lottery ever.