So I have a FlashForge AD5X with the MMU. It worked amazing out of the box, including flawlessly doing some TPU. They actually mentioned the MMU was designed with TPU in mind. That being said: I have been struggling with basic PLA, even after swapping to nozzle that has run only PLA (even though I only ran <10g of TPU through it). I am still new to a lot of this, and don’t feel experienced enough to fault the hardware. What I can say though is it does seem folks are specifically improving the ability of MMUs to handle flexibles. A big reason I got it was to be able to do ABS parts with TPU gaskets. Ask me in a few months.