Hi! I had two pipes joining to 1 pipe which then entered a water sieve. The first pipe has 500g polluted water at 29C, the 2nd pipe has 10kg polluted water at 5C. Upon merging before entering the sieve, the water temperature shows ~5.1C, can't remember exactly. The 10kg water enters sieve on next step, 10kg water then exits sieve at 29C.
I was able to resolve it in my game by deconstructing the exit pipe from the sieve and rebuilding it, after this, the water was exiting at ~5.1C as it should have.
I have no clue.