[2.0.23] Splitters filtered for spoilage sometimes ignore items that spoil after reaching them

[Preschool girl]

WHAT DID YOU DO
Set up a blue belt with a lane of Agri science packs and a lane of another science pack. Installed a splitter on the belt with a filter set to "spoilage."

WHAT HAPPENED
The two types of science packs flowed through the splitter ignoring it as expected. At some point, they got backed up and stopped as expected. Then the Agri science converted to spoilage and stayed right where it was.

12-07-2024, 21-46-28.png (540.53 KiB) Viewed 183 times

WHAT DID YOU EXPECT TO HAPPEN INSTEAD?
The spoilage should move through the splitter onto the other belt upon transition.

DOES THIS HAPPEN ALWAYS, ONCE, OR SOMETIMES?
It's happening on all my science belts. But it doesn't happen when I specifically test it with, e.g., nutrients and iron plates:

12-07-2024, 21-48-18.png (743.37 KiB) Viewed 183 times

Apologies if this is intended, or known. Relative newbie and didn't find anything on search.

[MechBFP]

There is a good chance there is still an agriculture science pack inside the splitter that hasn't spoiled yet.

How long did you wait?

[boskid]

Without save file there is not much i can do, just images are not enough to investigate what items are on belts and what is state of the splitter.

[MechBFP]

If you look at the top screenshot, just on the entrance to the splitter you can see a tiny bit of yellow, indicating there is still a science pack there. Maybe even a utility science pack that got accidentally put on the belt.

[boskid]

Ah yeah, there are some suspicious pixels there. In that case moving to Not a bug.