43915

I'm not sure, because I don't have a dual extruder printer and have never looked at the related settings, but to me that looks like a prime tower. Not sure why it would make one if your print is entirely TPU (no supports etc. in PLA) but you could check any settings related to "prime tower" and hopefully that's what it is and you can turn it off!

You might need to tweak the overhang angle setting. Looks like you've put it at 51 which might simply be too low for it to add support. Not sure why the tree supports show up, I rarely use those. But try increasing the angle value a bit and slice again, they should eventually appear for normal support as well.
 
Edit:
Of course I meant lowering the overhang angle setting. I downloaded your model and lowered it from 51 to 40 and it added supports just fine.