The Household Robot That Keeps Throwing Away the Wrong Trash

A new household robot with AI is supposed to clean up on its own.

It recognizes objects, sorts them, and automatically throws away obvious trash.

At first it works impressively well.

Empty packaging disappears, and scattered things are neatly put away.

But after a few days, the residents complain:

The robot has thrown away important notes, a craft sheet, and even a bill.

Everything was mistakenly classified as trash.

The robot was only supposed to help.

So why does it keep throwing away the wrong things?

Question:
Why can a cleaning robot confuse useful objects with trash?

Solution will be unlocked tomorrow.