[2.0.22] Rocket part ingredients won't be inserted if they have the "spoil-result" flag

[cackling.fiend]

I made this mod: https://mods.factorio.com/mod/hot-metals
It changes LDS to be a spoil result of hot LDS when crafted in the foundry.
This adds the "spoil-result" flag to the LDS item automatically, triggering the behavior that LDS won't be inserted as rocket part ingredient anymore.

Adding just this code `data.raw.item["low-density-structure"].flags = { "spoil-result" }` is enough to reproduce the bug. Inserters will then stop inserting LDS into rocket silos.