When using LTN and a train finished to unload for whatever reason, it happily returns to the depo with any leftover cargo.
Unfortunately it will take that cargo on its next journey, unloading any leftover items at the depo into a purple chest is easy enough,
but dealing with leftover fluids at the depo is simply absolute hell, unless you have like an auto-bottler or the
ltn-cleanup mod installed.
To solve this issue for me, i made this mod which removes the "or wait 120s" condition, so instead it will wait until it has been fully unloaded.
It will still cause clogs, but at least the trains get stuck at their intended offload station instead of taking the scenic route through the train depo.