It could be some kind of tick limitation, I don't know much details about how splitters work. However playing around with it a bit more. I found out that modifying splitter by either: - adding and removing a tile of belt to the bottom lane (either input or output) - rotating the splitter fixes the i...

From my testing the prio is irrelevant, also the same behaviour can be replicated with inserters. The slowdown seems to happen way before the splitter. After removing some items from the left side of the splitter it compresses again before reaching the splitter. It almost seems like a splitter sudde...

Can you provide a save with these setups or at least mod list?
I tried similar design with 75/s seablock belts but they behave properly and I don't know which mods give higher speed belts.

Also it's a bit unclear for me: is the copper belt required and does the splitter has to have a filter set?

Lately I noticed that some recipes started disappearing from the blueprints in my library. The reason for this has been due to switching between Seablock and Vanilla. (Though same issue happens with PY mods, haven't tested other overhaul mods.) For Seablock almost all fluid recipes are missing. For ...