Not sure if it's specific to the tendril explusion recipe, but that's what triggered it. Steps to reproduce:

• Have a folding engine with the tendril expulsion recipe set
• Put the cube in it (with less than 20k tendrils, not sure if there's a -minimum requirement, but I did it just now with 12k)
• Walk away
• Use remote view to change the recipe
• Cube and tendrils end up in the trash slots
• Mod starts spitting warnings about the cube being lost

Picking it up out of the trash slot stops the warnings. I noticed that it didn't apply the slowdown effect for a second or two, presumably when it -would- have given another warning.